From 9fa0f2eb5638b5863c573c0ef1922d4cb2c729d5 Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Wed, 18 Apr 2018 07:28:47 -0400
Subject: [PATCH 1/4] CMakeFindPackageMode: Perform platform-specific
 initialization

Since commit v3.1.0-rc1~565^2~3 (Add platform-specific initialization
step when enabling languages, 2014-04-29) the main enable-language logic
includes the `CMakeSystemSpecificInitialize` module to perform
platform-specific initialization based on `CMAKE_SYSTEM_NAME`.  This
should be done during `cmake --find-package` mode too.
---
 Modules/CMakeFindPackageMode.cmake | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Modules/CMakeFindPackageMode.cmake b/Modules/CMakeFindPackageMode.cmake
index 7c41d49e27..ec3652cfa2 100644
--- a/Modules/CMakeFindPackageMode.cmake
+++ b/Modules/CMakeFindPackageMode.cmake
@@ -65,6 +65,8 @@ if("${CMAKE_SYSTEM_NAME}" MATCHES Darwin  AND  "${COMPILER_ID}" MATCHES GNU)
   set(CMAKE_${LANGUAGE}_OSX_DEPLOYMENT_TARGET_FLAG "")
 endif()
 
+include(CMakeSystemSpecificInitialize)
+
 # Also load the system specific file, which sets up e.g. the search paths.
 # This makes the FIND_XXX() calls work much better
 include(CMakeSystemSpecificInformation)

From 84f9f63fccdadb9b8a0bdb3260a0c7a3f71cb251 Mon Sep 17 00:00:00 2001
From: Gregor Jasny <gjasny@googlemail.com>
Date: Sun, 1 Apr 2018 22:49:59 +0200
Subject: [PATCH 2/4] Modules: Introduce CMAKE_EFFECTIVE_SYSTEM_NAME to lookup
 compiler info

Create a `CMAKE_EFFECTIVE_SYSTEM_NAME` variable to use for looking
up compiler information modules instead of using `CMAKE_SYSTEM_NAME`
directly.  This will allow multiple platforms to share the same set
of compiler information modules without spelling out all of them.

Issue: #17870
---
 Modules/CMakeASMInformation.cmake           | 8 ++++----
 Modules/CMakeCInformation.cmake             | 8 ++++----
 Modules/CMakeCUDAInformation.cmake          | 4 ++--
 Modules/CMakeCXXInformation.cmake           | 8 ++++----
 Modules/CMakeFortranInformation.cmake       | 4 ++--
 Modules/CMakeLanguageInformation.cmake      | 4 ++--
 Modules/CMakeSwiftInformation.cmake         | 4 ++--
 Modules/CMakeSystemSpecificInitialize.cmake | 8 ++++++++
 8 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/Modules/CMakeASMInformation.cmake b/Modules/CMakeASMInformation.cmake
index 125c4e3723..6b7373067e 100644
--- a/Modules/CMakeASMInformation.cmake
+++ b/Modules/CMakeASMInformation.cmake
@@ -29,15 +29,15 @@ if(NOT _INCLUDED_FILE)
 endif()
 
 if(CMAKE_SYSTEM_PROCESSOR)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_ASM${ASM_DIALECT}_COMPILER_ID}-ASM${ASM_DIALECT}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL  RESULT_VARIABLE _INCLUDED_FILE)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_ASM${ASM_DIALECT}_COMPILER_ID}-ASM${ASM_DIALECT}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL  RESULT_VARIABLE _INCLUDED_FILE)
   if(NOT _INCLUDED_FILE)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif()
 endif()
 
-include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_ASM${ASM_DIALECT}_COMPILER_ID}-ASM${ASM_DIALECT} OPTIONAL  RESULT_VARIABLE _INCLUDED_FILE)
+include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_ASM${ASM_DIALECT}_COMPILER_ID}-ASM${ASM_DIALECT} OPTIONAL  RESULT_VARIABLE _INCLUDED_FILE)
 if(NOT _INCLUDED_FILE)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL)
 endif()
 
 # This should be included before the _INIT variables are
diff --git a/Modules/CMakeCInformation.cmake b/Modules/CMakeCInformation.cmake
index 1e46cacaac..df43559c95 100644
--- a/Modules/CMakeCInformation.cmake
+++ b/Modules/CMakeCInformation.cmake
@@ -35,21 +35,21 @@ endif()
 # load a hardware specific file, mostly useful for embedded compilers
 if(CMAKE_SYSTEM_PROCESSOR)
   if(CMAKE_C_COMPILER_ID)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_C_COMPILER_ID}-C-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_C_COMPILER_ID}-C-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
   endif()
   if (NOT _INCLUDED_FILE)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif ()
 endif()
 
 
 # load the system- and compiler specific files
 if(CMAKE_C_COMPILER_ID)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_C_COMPILER_ID}-C
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_C_COMPILER_ID}-C
     OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
 endif()
 if (NOT _INCLUDED_FILE)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME}
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME}
     OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
 endif ()
 
diff --git a/Modules/CMakeCUDAInformation.cmake b/Modules/CMakeCUDAInformation.cmake
index 4788cbf3d0..479493b0e4 100644
--- a/Modules/CMakeCUDAInformation.cmake
+++ b/Modules/CMakeCUDAInformation.cmake
@@ -17,9 +17,9 @@ endif()
 if(CMAKE_CUDA_COMPILER_ID)
   # load a hardware specific file, mostly useful for embedded compilers
   if(CMAKE_SYSTEM_PROCESSOR)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_CUDA_COMPILER_ID}-CUDA-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_CUDA_COMPILER_ID}-CUDA-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif()
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_CUDA_COMPILER_ID}-CUDA OPTIONAL)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_CUDA_COMPILER_ID}-CUDA OPTIONAL)
 endif()
 
 
diff --git a/Modules/CMakeCXXInformation.cmake b/Modules/CMakeCXXInformation.cmake
index 9ac9560e08..2975874d84 100644
--- a/Modules/CMakeCXXInformation.cmake
+++ b/Modules/CMakeCXXInformation.cmake
@@ -36,19 +36,19 @@ endif()
 # load a hardware specific file, mostly useful for embedded compilers
 if(CMAKE_SYSTEM_PROCESSOR)
   if(CMAKE_CXX_COMPILER_ID)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_CXX_COMPILER_ID}-CXX-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_CXX_COMPILER_ID}-CXX-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
   endif()
   if (NOT _INCLUDED_FILE)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME}-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif ()
 endif()
 
 # load the system- and compiler specific files
 if(CMAKE_CXX_COMPILER_ID)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_CXX_COMPILER_ID}-CXX OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_CXX_COMPILER_ID}-CXX OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
 endif()
 if (NOT _INCLUDED_FILE)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL
           RESULT_VARIABLE _INCLUDED_FILE)
 endif ()
 
diff --git a/Modules/CMakeFortranInformation.cmake b/Modules/CMakeFortranInformation.cmake
index 5f028e4f3e..cceac83c69 100644
--- a/Modules/CMakeFortranInformation.cmake
+++ b/Modules/CMakeFortranInformation.cmake
@@ -22,10 +22,10 @@ if(CMAKE_COMPILER_IS_GNUG77)
   set(CMAKE_BASE_NAME g77)
 endif()
 if(CMAKE_Fortran_COMPILER_ID)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_Fortran_COMPILER_ID}-Fortran OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_Fortran_COMPILER_ID}-Fortran OPTIONAL RESULT_VARIABLE _INCLUDED_FILE)
 endif()
 if (NOT _INCLUDED_FILE)
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_BASE_NAME} OPTIONAL
           RESULT_VARIABLE _INCLUDED_FILE)
 endif ()
 
diff --git a/Modules/CMakeLanguageInformation.cmake b/Modules/CMakeLanguageInformation.cmake
index 18c8624faa..674ab86969 100644
--- a/Modules/CMakeLanguageInformation.cmake
+++ b/Modules/CMakeLanguageInformation.cmake
@@ -9,10 +9,10 @@
 macro(__cmake_include_compiler_wrapper lang)
   set(_INCLUDED_WRAPPER_FILE 0)
   if (CMAKE_${lang}_COMPILER_ID)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_${lang}_COMPILER_WRAPPER}-${CMAKE_${lang}_COMPILER_ID}-${lang} OPTIONAL RESULT_VARIABLE _INCLUDED_WRAPPER_FILE)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_${lang}_COMPILER_WRAPPER}-${CMAKE_${lang}_COMPILER_ID}-${lang} OPTIONAL RESULT_VARIABLE _INCLUDED_WRAPPER_FILE)
   endif()
   if (NOT _INCLUDED_WRAPPER_FILE)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_${lang}_COMPILER_WRAPPER}-${lang} OPTIONAL RESULT_VARIABLE _INCLUDED_WRAPPER_FILE)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_${lang}_COMPILER_WRAPPER}-${lang} OPTIONAL RESULT_VARIABLE _INCLUDED_WRAPPER_FILE)
   endif ()
 
   # No platform - wrapper - lang information so maybe there's just wrapper - lang information
diff --git a/Modules/CMakeSwiftInformation.cmake b/Modules/CMakeSwiftInformation.cmake
index d9b408d3be..07ba6d077c 100644
--- a/Modules/CMakeSwiftInformation.cmake
+++ b/Modules/CMakeSwiftInformation.cmake
@@ -14,9 +14,9 @@ endif()
 if(CMAKE_Swift_COMPILER_ID)
   # load a hardware specific file, mostly useful for embedded compilers
   if(CMAKE_SYSTEM_PROCESSOR)
-    include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_Swift_COMPILER_ID}-Swift-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
+    include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_Swift_COMPILER_ID}-Swift-${CMAKE_SYSTEM_PROCESSOR} OPTIONAL)
   endif()
-  include(Platform/${CMAKE_SYSTEM_NAME}-${CMAKE_Swift_COMPILER_ID}-Swift OPTIONAL)
+  include(Platform/${CMAKE_EFFECTIVE_SYSTEM_NAME}-${CMAKE_Swift_COMPILER_ID}-Swift OPTIONAL)
 endif()
 
 # for most systems a module is the same as a shared library
diff --git a/Modules/CMakeSystemSpecificInitialize.cmake b/Modules/CMakeSystemSpecificInitialize.cmake
index 6200e9c0d3..629f226c13 100644
--- a/Modules/CMakeSystemSpecificInitialize.cmake
+++ b/Modules/CMakeSystemSpecificInitialize.cmake
@@ -5,6 +5,14 @@
 # This file is included by cmGlobalGenerator::EnableLanguage.
 # It is included before the compiler has been determined.
 
+# The CMAKE_EFFECTIVE_SYSTEM_NAME is used to load compiler and compiler
+# wrapper configuration files. By default it equals to CMAKE_SYSTEM_NAME
+# but could be overridden in the ${CMAKE_SYSTEM_NAME}-Initialize files.
+#
+# It is useful to share the same aforementioned configuration files and
+# avoids duplicating them in case of tightly related platforms.
+set(CMAKE_EFFECTIVE_SYSTEM_NAME "${CMAKE_SYSTEM_NAME}")
+
 include(Platform/${CMAKE_SYSTEM_NAME}-Initialize OPTIONAL)
 
 set(CMAKE_SYSTEM_SPECIFIC_INITIALIZE_LOADED 1)

From e95b3fd9bbca94cb5f217847031c9c8f393aee78 Mon Sep 17 00:00:00 2001
From: Gregor Jasny <gjasny@googlemail.com>
Date: Sun, 1 Apr 2018 22:49:59 +0200
Subject: [PATCH 3/4] Apple: Use CMAKE_EFFECTIVE_SYSTEM_NAME to share compiler
 info

Apple platforms macOS, iOS, tvOS, and watchOS can all share the same
compiler information.  Rename `Darwin-*` modules to `Apple-*` and load
them all through `CMAKE_EFFECTIVE_SYSTEM_NAME`.  This saves duplication
of 4 * 21 compiler information modules.

Issue: #17870
---
 Modules/CMakeSystemSpecificInitialize.cmake                 | 5 +++++
 ...rwin-Absoft-Fortran.cmake => Apple-Absoft-Fortran.cmake} | 0
 .../{Darwin-AppleClang-C.cmake => Apple-AppleClang-C.cmake} | 2 +-
 ...rwin-AppleClang-CXX.cmake => Apple-AppleClang-CXX.cmake} | 2 +-
 Modules/Platform/Apple-Clang-C.cmake                        | 2 ++
 Modules/Platform/Apple-Clang-CXX.cmake                      | 2 ++
 Modules/Platform/{Darwin-Clang.cmake => Apple-Clang.cmake}  | 6 +++---
 Modules/Platform/{Darwin-GNU-C.cmake => Apple-GNU-C.cmake}  | 4 ++--
 .../Platform/{Darwin-GNU-CXX.cmake => Apple-GNU-CXX.cmake}  | 4 ++--
 .../{Darwin-GNU-Fortran.cmake => Apple-GNU-Fortran.cmake}   | 4 ++--
 Modules/Platform/{Darwin-GNU.cmake => Apple-GNU.cmake}      | 6 +++---
 Modules/Platform/Apple-Intel-C.cmake                        | 2 ++
 Modules/Platform/Apple-Intel-CXX.cmake                      | 2 ++
 ...Darwin-Intel-Fortran.cmake => Apple-Intel-Fortran.cmake} | 4 ++--
 Modules/Platform/{Darwin-Intel.cmake => Apple-Intel.cmake}  | 6 +++---
 .../{Darwin-NAG-Fortran.cmake => Apple-NAG-Fortran.cmake}   | 0
 .../{Darwin-NVIDIA-CUDA.cmake => Apple-NVIDIA-CUDA.cmake}   | 0
 Modules/Platform/Apple-PGI-C.cmake                          | 2 ++
 Modules/Platform/Apple-PGI-CXX.cmake                        | 2 ++
 Modules/Platform/Apple-PGI-Fortran.cmake                    | 2 ++
 Modules/Platform/{Darwin-PGI.cmake => Apple-PGI.cmake}      | 6 +++---
 Modules/Platform/Apple-VisualAge-C.cmake                    | 1 +
 Modules/Platform/Apple-VisualAge-CXX.cmake                  | 1 +
 Modules/Platform/{Darwin-XL-C.cmake => Apple-XL-C.cmake}    | 0
 .../Platform/{Darwin-XL-CXX.cmake => Apple-XL-CXX.cmake}    | 0
 Modules/Platform/Darwin-Clang-C.cmake                       | 2 --
 Modules/Platform/Darwin-Clang-CXX.cmake                     | 2 --
 Modules/Platform/Darwin-Initialize.cmake                    | 4 ++++
 Modules/Platform/Darwin-Intel-C.cmake                       | 2 --
 Modules/Platform/Darwin-Intel-CXX.cmake                     | 2 --
 Modules/Platform/Darwin-PGI-C.cmake                         | 2 --
 Modules/Platform/Darwin-PGI-CXX.cmake                       | 2 --
 Modules/Platform/Darwin-PGI-Fortran.cmake                   | 2 --
 Modules/Platform/Darwin-VisualAge-C.cmake                   | 1 -
 Modules/Platform/Darwin-VisualAge-CXX.cmake                 | 1 -
 35 files changed, 47 insertions(+), 38 deletions(-)
 rename Modules/Platform/{Darwin-Absoft-Fortran.cmake => Apple-Absoft-Fortran.cmake} (100%)
 rename Modules/Platform/{Darwin-AppleClang-C.cmake => Apple-AppleClang-C.cmake} (83%)
 rename Modules/Platform/{Darwin-AppleClang-CXX.cmake => Apple-AppleClang-CXX.cmake} (83%)
 create mode 100644 Modules/Platform/Apple-Clang-C.cmake
 create mode 100644 Modules/Platform/Apple-Clang-CXX.cmake
 rename Modules/Platform/{Darwin-Clang.cmake => Apple-Clang.cmake} (94%)
 rename Modules/Platform/{Darwin-GNU-C.cmake => Apple-GNU-C.cmake} (57%)
 rename Modules/Platform/{Darwin-GNU-CXX.cmake => Apple-GNU-CXX.cmake} (58%)
 rename Modules/Platform/{Darwin-GNU-Fortran.cmake => Apple-GNU-Fortran.cmake} (86%)
 rename Modules/Platform/{Darwin-GNU.cmake => Apple-GNU.cmake} (96%)
 create mode 100644 Modules/Platform/Apple-Intel-C.cmake
 create mode 100644 Modules/Platform/Apple-Intel-CXX.cmake
 rename Modules/Platform/{Darwin-Intel-Fortran.cmake => Apple-Intel-Fortran.cmake} (81%)
 rename Modules/Platform/{Darwin-Intel.cmake => Apple-Intel.cmake} (87%)
 rename Modules/Platform/{Darwin-NAG-Fortran.cmake => Apple-NAG-Fortran.cmake} (100%)
 rename Modules/Platform/{Darwin-NVIDIA-CUDA.cmake => Apple-NVIDIA-CUDA.cmake} (100%)
 create mode 100644 Modules/Platform/Apple-PGI-C.cmake
 create mode 100644 Modules/Platform/Apple-PGI-CXX.cmake
 create mode 100644 Modules/Platform/Apple-PGI-Fortran.cmake
 rename Modules/Platform/{Darwin-PGI.cmake => Apple-PGI.cmake} (83%)
 create mode 100644 Modules/Platform/Apple-VisualAge-C.cmake
 create mode 100644 Modules/Platform/Apple-VisualAge-CXX.cmake
 rename Modules/Platform/{Darwin-XL-C.cmake => Apple-XL-C.cmake} (100%)
 rename Modules/Platform/{Darwin-XL-CXX.cmake => Apple-XL-CXX.cmake} (100%)
 delete mode 100644 Modules/Platform/Darwin-Clang-C.cmake
 delete mode 100644 Modules/Platform/Darwin-Clang-CXX.cmake
 delete mode 100644 Modules/Platform/Darwin-Intel-C.cmake
 delete mode 100644 Modules/Platform/Darwin-Intel-CXX.cmake
 delete mode 100644 Modules/Platform/Darwin-PGI-C.cmake
 delete mode 100644 Modules/Platform/Darwin-PGI-CXX.cmake
 delete mode 100644 Modules/Platform/Darwin-PGI-Fortran.cmake
 delete mode 100644 Modules/Platform/Darwin-VisualAge-C.cmake
 delete mode 100644 Modules/Platform/Darwin-VisualAge-CXX.cmake

diff --git a/Modules/CMakeSystemSpecificInitialize.cmake b/Modules/CMakeSystemSpecificInitialize.cmake
index 629f226c13..de4d7f5728 100644
--- a/Modules/CMakeSystemSpecificInitialize.cmake
+++ b/Modules/CMakeSystemSpecificInitialize.cmake
@@ -11,6 +11,11 @@
 #
 # It is useful to share the same aforementioned configuration files and
 # avoids duplicating them in case of tightly related platforms.
+#
+# An example are the platforms supported by Xcode (macOS, iOS, tvOS,
+# and watchOS). For all of those the CMAKE_EFFECTIVE_SYSTEM_NAME is
+# set to Apple which results in using
+# Platfom/Apple-AppleClang-CXX.cmake for the Apple C++ compiler.
 set(CMAKE_EFFECTIVE_SYSTEM_NAME "${CMAKE_SYSTEM_NAME}")
 
 include(Platform/${CMAKE_SYSTEM_NAME}-Initialize OPTIONAL)
diff --git a/Modules/Platform/Darwin-Absoft-Fortran.cmake b/Modules/Platform/Apple-Absoft-Fortran.cmake
similarity index 100%
rename from Modules/Platform/Darwin-Absoft-Fortran.cmake
rename to Modules/Platform/Apple-Absoft-Fortran.cmake
diff --git a/Modules/Platform/Darwin-AppleClang-C.cmake b/Modules/Platform/Apple-AppleClang-C.cmake
similarity index 83%
rename from Modules/Platform/Darwin-AppleClang-C.cmake
rename to Modules/Platform/Apple-AppleClang-C.cmake
index 3216b29094..f45ccf4134 100644
--- a/Modules/Platform/Darwin-AppleClang-C.cmake
+++ b/Modules/Platform/Apple-AppleClang-C.cmake
@@ -1,4 +1,4 @@
-include(Platform/Darwin-Clang-C)
+include(Platform/Apple-Clang-C)
 if(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.2)
   set(CMAKE_C_SYSTEM_FRAMEWORK_SEARCH_FLAG "-iframework ")
 else()
diff --git a/Modules/Platform/Darwin-AppleClang-CXX.cmake b/Modules/Platform/Apple-AppleClang-CXX.cmake
similarity index 83%
rename from Modules/Platform/Darwin-AppleClang-CXX.cmake
rename to Modules/Platform/Apple-AppleClang-CXX.cmake
index 3fedf8c076..1128204cf4 100644
--- a/Modules/Platform/Darwin-AppleClang-CXX.cmake
+++ b/Modules/Platform/Apple-AppleClang-CXX.cmake
@@ -1,4 +1,4 @@
-include(Platform/Darwin-Clang-CXX)
+include(Platform/Apple-Clang-CXX)
 if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.2)
   set(CMAKE_CXX_SYSTEM_FRAMEWORK_SEARCH_FLAG "-iframework ")
 else()
diff --git a/Modules/Platform/Apple-Clang-C.cmake b/Modules/Platform/Apple-Clang-C.cmake
new file mode 100644
index 0000000000..4d0dc82943
--- /dev/null
+++ b/Modules/Platform/Apple-Clang-C.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-Clang)
+__apple_compiler_clang(C)
diff --git a/Modules/Platform/Apple-Clang-CXX.cmake b/Modules/Platform/Apple-Clang-CXX.cmake
new file mode 100644
index 0000000000..6c1ddc104d
--- /dev/null
+++ b/Modules/Platform/Apple-Clang-CXX.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-Clang)
+__apple_compiler_clang(CXX)
diff --git a/Modules/Platform/Darwin-Clang.cmake b/Modules/Platform/Apple-Clang.cmake
similarity index 94%
rename from Modules/Platform/Darwin-Clang.cmake
rename to Modules/Platform/Apple-Clang.cmake
index f8a07ec2dd..70fc75e9d5 100644
--- a/Modules/Platform/Darwin-Clang.cmake
+++ b/Modules/Platform/Apple-Clang.cmake
@@ -3,12 +3,12 @@
 
 
 # This module is shared by multiple languages; use include blocker.
-if(__DARWIN_COMPILER_CLANG)
+if(__APPLE_COMPILER_CLANG)
   return()
 endif()
-set(__DARWIN_COMPILER_CLANG 1)
+set(__APPLE_COMPILER_CLANG 1)
 
-macro(__darwin_compiler_clang lang)
+macro(__apple_compiler_clang lang)
   set(CMAKE_${lang}_VERBOSE_FLAG "-v -Wl,-v") # also tell linker to print verbose output
   set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "-dynamiclib -Wl,-headerpad_max_install_names")
   set(CMAKE_SHARED_MODULE_CREATE_${lang}_FLAGS "-bundle -Wl,-headerpad_max_install_names")
diff --git a/Modules/Platform/Darwin-GNU-C.cmake b/Modules/Platform/Apple-GNU-C.cmake
similarity index 57%
rename from Modules/Platform/Darwin-GNU-C.cmake
rename to Modules/Platform/Apple-GNU-C.cmake
index efdfd0014a..5481c99d84 100644
--- a/Modules/Platform/Darwin-GNU-C.cmake
+++ b/Modules/Platform/Apple-GNU-C.cmake
@@ -1,4 +1,4 @@
-include(Platform/Darwin-GNU)
-__darwin_compiler_gnu(C)
+include(Platform/Apple-GNU)
+__apple_compiler_gnu(C)
 cmake_gnu_set_sysroot_flag(C)
 cmake_gnu_set_osx_deployment_target_flag(C)
diff --git a/Modules/Platform/Darwin-GNU-CXX.cmake b/Modules/Platform/Apple-GNU-CXX.cmake
similarity index 58%
rename from Modules/Platform/Darwin-GNU-CXX.cmake
rename to Modules/Platform/Apple-GNU-CXX.cmake
index e3c2ea7c57..727f726410 100644
--- a/Modules/Platform/Darwin-GNU-CXX.cmake
+++ b/Modules/Platform/Apple-GNU-CXX.cmake
@@ -1,4 +1,4 @@
-include(Platform/Darwin-GNU)
-__darwin_compiler_gnu(CXX)
+include(Platform/Apple-GNU)
+__apple_compiler_gnu(CXX)
 cmake_gnu_set_sysroot_flag(CXX)
 cmake_gnu_set_osx_deployment_target_flag(CXX)
diff --git a/Modules/Platform/Darwin-GNU-Fortran.cmake b/Modules/Platform/Apple-GNU-Fortran.cmake
similarity index 86%
rename from Modules/Platform/Darwin-GNU-Fortran.cmake
rename to Modules/Platform/Apple-GNU-Fortran.cmake
index 568d79b0c2..2f53603cbc 100644
--- a/Modules/Platform/Darwin-GNU-Fortran.cmake
+++ b/Modules/Platform/Apple-GNU-Fortran.cmake
@@ -1,8 +1,8 @@
 # Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
 # file Copyright.txt or https://cmake.org/licensing for details.
 
-include(Platform/Darwin-GNU)
-__darwin_compiler_gnu(Fortran)
+include(Platform/Apple-GNU)
+__apple_compiler_gnu(Fortran)
 cmake_gnu_set_sysroot_flag(Fortran)
 cmake_gnu_set_osx_deployment_target_flag(Fortran)
 
diff --git a/Modules/Platform/Darwin-GNU.cmake b/Modules/Platform/Apple-GNU.cmake
similarity index 96%
rename from Modules/Platform/Darwin-GNU.cmake
rename to Modules/Platform/Apple-GNU.cmake
index 9f9ef01cb4..9985dddd7d 100644
--- a/Modules/Platform/Darwin-GNU.cmake
+++ b/Modules/Platform/Apple-GNU.cmake
@@ -3,12 +3,12 @@
 
 
 # This module is shared by multiple languages; use include blocker.
-if(__DARWIN_COMPILER_GNU)
+if(__APPLE_COMPILER_GNU)
   return()
 endif()
-set(__DARWIN_COMPILER_GNU 1)
+set(__APPLE_COMPILER_GNU 1)
 
-macro(__darwin_compiler_gnu lang)
+macro(__apple_compiler_gnu lang)
   set(CMAKE_${lang}_VERBOSE_FLAG "-v -Wl,-v") # also tell linker to print verbose output
   # GNU does not have -shared on OS X
   set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "-dynamiclib -Wl,-headerpad_max_install_names")
diff --git a/Modules/Platform/Apple-Intel-C.cmake b/Modules/Platform/Apple-Intel-C.cmake
new file mode 100644
index 0000000000..95bb270d3d
--- /dev/null
+++ b/Modules/Platform/Apple-Intel-C.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-Intel)
+__apple_compiler_intel(C)
diff --git a/Modules/Platform/Apple-Intel-CXX.cmake b/Modules/Platform/Apple-Intel-CXX.cmake
new file mode 100644
index 0000000000..b87e512dfc
--- /dev/null
+++ b/Modules/Platform/Apple-Intel-CXX.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-Intel)
+__apple_compiler_intel(CXX)
diff --git a/Modules/Platform/Darwin-Intel-Fortran.cmake b/Modules/Platform/Apple-Intel-Fortran.cmake
similarity index 81%
rename from Modules/Platform/Darwin-Intel-Fortran.cmake
rename to Modules/Platform/Apple-Intel-Fortran.cmake
index 2299da9cec..e54e237623 100644
--- a/Modules/Platform/Darwin-Intel-Fortran.cmake
+++ b/Modules/Platform/Apple-Intel-Fortran.cmake
@@ -1,8 +1,8 @@
 # Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
 # file Copyright.txt or https://cmake.org/licensing for details.
 
-include(Platform/Darwin-Intel)
-__darwin_compiler_intel(Fortran)
+include(Platform/Apple-Intel)
+__apple_compiler_intel(Fortran)
 
 set(CMAKE_Fortran_OSX_COMPATIBILITY_VERSION_FLAG "-compatibility_version ")
 set(CMAKE_Fortran_OSX_CURRENT_VERSION_FLAG "-current_version ")
diff --git a/Modules/Platform/Darwin-Intel.cmake b/Modules/Platform/Apple-Intel.cmake
similarity index 87%
rename from Modules/Platform/Darwin-Intel.cmake
rename to Modules/Platform/Apple-Intel.cmake
index dd33cec4b9..9f92d9592a 100644
--- a/Modules/Platform/Darwin-Intel.cmake
+++ b/Modules/Platform/Apple-Intel.cmake
@@ -3,12 +3,12 @@
 
 
 # This module is shared by multiple languages; use include blocker.
-if(__DARWIN_COMPILER_INTEL)
+if(__APPLE_COMPILER_INTEL)
   return()
 endif()
-set(__DARWIN_COMPILER_INTEL 1)
+set(__APPLE_COMPILER_INTEL 1)
 
-macro(__darwin_compiler_intel lang)
+macro(__apple_compiler_intel lang)
   set(CMAKE_${lang}_VERBOSE_FLAG "-v -Wl,-v") # also tell linker to print verbose output
   set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "-dynamiclib -Wl,-headerpad_max_install_names")
   set(CMAKE_SHARED_MODULE_CREATE_${lang}_FLAGS "-bundle -Wl,-headerpad_max_install_names")
diff --git a/Modules/Platform/Darwin-NAG-Fortran.cmake b/Modules/Platform/Apple-NAG-Fortran.cmake
similarity index 100%
rename from Modules/Platform/Darwin-NAG-Fortran.cmake
rename to Modules/Platform/Apple-NAG-Fortran.cmake
diff --git a/Modules/Platform/Darwin-NVIDIA-CUDA.cmake b/Modules/Platform/Apple-NVIDIA-CUDA.cmake
similarity index 100%
rename from Modules/Platform/Darwin-NVIDIA-CUDA.cmake
rename to Modules/Platform/Apple-NVIDIA-CUDA.cmake
diff --git a/Modules/Platform/Apple-PGI-C.cmake b/Modules/Platform/Apple-PGI-C.cmake
new file mode 100644
index 0000000000..1e117247b1
--- /dev/null
+++ b/Modules/Platform/Apple-PGI-C.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-PGI)
+__apple_compiler_pgi(C)
diff --git a/Modules/Platform/Apple-PGI-CXX.cmake b/Modules/Platform/Apple-PGI-CXX.cmake
new file mode 100644
index 0000000000..aa5daf7dd4
--- /dev/null
+++ b/Modules/Platform/Apple-PGI-CXX.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-PGI)
+__apple_compiler_pgi(CXX)
diff --git a/Modules/Platform/Apple-PGI-Fortran.cmake b/Modules/Platform/Apple-PGI-Fortran.cmake
new file mode 100644
index 0000000000..1e3e4b1a7b
--- /dev/null
+++ b/Modules/Platform/Apple-PGI-Fortran.cmake
@@ -0,0 +1,2 @@
+include(Platform/Apple-PGI)
+__apple_compiler_pgi(Fortran)
diff --git a/Modules/Platform/Darwin-PGI.cmake b/Modules/Platform/Apple-PGI.cmake
similarity index 83%
rename from Modules/Platform/Darwin-PGI.cmake
rename to Modules/Platform/Apple-PGI.cmake
index 04479a8979..a68c08dea7 100644
--- a/Modules/Platform/Darwin-PGI.cmake
+++ b/Modules/Platform/Apple-PGI.cmake
@@ -2,12 +2,12 @@
 # file Copyright.txt or https://cmake.org/licensing for details.
 
 # This module is shared by multiple languages; use include blocker.
-if(__DARWIN_COMPILER_PGI)
+if(__APPLE_COMPILER_PGI)
   return()
 endif()
-set(__DARWIN_COMPILER_PGI 1)
+set(__APPLE_COMPILER_PGI 1)
 
-macro(__darwin_compiler_pgi lang)
+macro(__apple_compiler_pgi lang)
   set(CMAKE_${lang}_OSX_COMPATIBILITY_VERSION_FLAG "-Wl,-compatibility_version,")
   set(CMAKE_${lang}_OSX_CURRENT_VERSION_FLAG "-Wl,-current_version,")
   set(CMAKE_SHARED_LIBRARY_SONAME_${lang}_FLAG "-Wl,-install_name")
diff --git a/Modules/Platform/Apple-VisualAge-C.cmake b/Modules/Platform/Apple-VisualAge-C.cmake
new file mode 100644
index 0000000000..7fa603231a
--- /dev/null
+++ b/Modules/Platform/Apple-VisualAge-C.cmake
@@ -0,0 +1 @@
+include(Platform/Apple-XL-C)
diff --git a/Modules/Platform/Apple-VisualAge-CXX.cmake b/Modules/Platform/Apple-VisualAge-CXX.cmake
new file mode 100644
index 0000000000..12dd34740f
--- /dev/null
+++ b/Modules/Platform/Apple-VisualAge-CXX.cmake
@@ -0,0 +1 @@
+include(Platform/Apple-XL-CXX)
diff --git a/Modules/Platform/Darwin-XL-C.cmake b/Modules/Platform/Apple-XL-C.cmake
similarity index 100%
rename from Modules/Platform/Darwin-XL-C.cmake
rename to Modules/Platform/Apple-XL-C.cmake
diff --git a/Modules/Platform/Darwin-XL-CXX.cmake b/Modules/Platform/Apple-XL-CXX.cmake
similarity index 100%
rename from Modules/Platform/Darwin-XL-CXX.cmake
rename to Modules/Platform/Apple-XL-CXX.cmake
diff --git a/Modules/Platform/Darwin-Clang-C.cmake b/Modules/Platform/Darwin-Clang-C.cmake
deleted file mode 100644
index 0a1502ea9b..0000000000
--- a/Modules/Platform/Darwin-Clang-C.cmake
+++ /dev/null
@@ -1,2 +0,0 @@
-include(Platform/Darwin-Clang)
-__darwin_compiler_clang(C)
diff --git a/Modules/Platform/Darwin-Clang-CXX.cmake b/Modules/Platform/Darwin-Clang-CXX.cmake
deleted file mode 100644
index f8e8d888e7..0000000000
--- a/Modules/Platform/Darwin-Clang-CXX.cmake
+++ /dev/null
@@ -1,2 +0,0 @@
-include(Platform/Darwin-Clang)
-__darwin_compiler_clang(CXX)
diff --git a/Modules/Platform/Darwin-Initialize.cmake b/Modules/Platform/Darwin-Initialize.cmake
index b539e457d1..3db77aacbb 100644
--- a/Modules/Platform/Darwin-Initialize.cmake
+++ b/Modules/Platform/Darwin-Initialize.cmake
@@ -20,6 +20,10 @@ execute_process(COMMAND sw_vers -productVersion
 set(CMAKE_OSX_ARCHITECTURES "$ENV{CMAKE_OSX_ARCHITECTURES}" CACHE STRING
   "Build architectures for OSX")
 
+# macOS, iOS, tvOS, and watchOS should lookup compilers from
+# Platform/Apple-${CMAKE_CXX_COMPILER_ID}-<LANG>
+set(CMAKE_EFFECTIVE_SYSTEM_NAME "Apple")
+
 #----------------------------------------------------------------------------
 # _CURRENT_OSX_VERSION - as a two-component string: 10.5, 10.6, ...
 #
diff --git a/Modules/Platform/Darwin-Intel-C.cmake b/Modules/Platform/Darwin-Intel-C.cmake
deleted file mode 100644
index 81c630f4ad..0000000000
--- a/Modules/Platform/Darwin-Intel-C.cmake
+++ /dev/null
@@ -1,2 +0,0 @@
-include(Platform/Darwin-Intel)
-__darwin_compiler_intel(C)
diff --git a/Modules/Platform/Darwin-Intel-CXX.cmake b/Modules/Platform/Darwin-Intel-CXX.cmake
deleted file mode 100644
index 90ae53be32..0000000000
--- a/Modules/Platform/Darwin-Intel-CXX.cmake
+++ /dev/null
@@ -1,2 +0,0 @@
-include(Platform/Darwin-Intel)
-__darwin_compiler_intel(CXX)
diff --git a/Modules/Platform/Darwin-PGI-C.cmake b/Modules/Platform/Darwin-PGI-C.cmake
deleted file mode 100644
index 790919b08e..0000000000
--- a/Modules/Platform/Darwin-PGI-C.cmake
+++ /dev/null
@@ -1,2 +0,0 @@
-include(Platform/Darwin-PGI)
-__darwin_compiler_pgi(C)
diff --git a/Modules/Platform/Darwin-PGI-CXX.cmake b/Modules/Platform/Darwin-PGI-CXX.cmake
deleted file mode 100644
index ceaed71528..0000000000
--- a/Modules/Platform/Darwin-PGI-CXX.cmake
+++ /dev/null
@@ -1,2 +0,0 @@
-include(Platform/Darwin-PGI)
-__darwin_compiler_pgi(CXX)
diff --git a/Modules/Platform/Darwin-PGI-Fortran.cmake b/Modules/Platform/Darwin-PGI-Fortran.cmake
deleted file mode 100644
index 146807ba9b..0000000000
--- a/Modules/Platform/Darwin-PGI-Fortran.cmake
+++ /dev/null
@@ -1,2 +0,0 @@
-include(Platform/Darwin-PGI)
-__darwin_compiler_pgi(Fortran)
diff --git a/Modules/Platform/Darwin-VisualAge-C.cmake b/Modules/Platform/Darwin-VisualAge-C.cmake
deleted file mode 100644
index 859914f867..0000000000
--- a/Modules/Platform/Darwin-VisualAge-C.cmake
+++ /dev/null
@@ -1 +0,0 @@
-include(Platform/Darwin-XL-C)
diff --git a/Modules/Platform/Darwin-VisualAge-CXX.cmake b/Modules/Platform/Darwin-VisualAge-CXX.cmake
deleted file mode 100644
index 46c1005df9..0000000000
--- a/Modules/Platform/Darwin-VisualAge-CXX.cmake
+++ /dev/null
@@ -1 +0,0 @@
-include(Platform/Darwin-XL-CXX)

From 459739678443d2d2074d6e1475e4267c6c110e05 Mon Sep 17 00:00:00 2001
From: Gregor Jasny <gjasny@googlemail.com>
Date: Sun, 15 Apr 2018 21:47:10 +0200
Subject: [PATCH 4/4] Apple: Use include_guard() within compiler config

---
 Modules/Platform/Apple-Clang.cmake | 5 +----
 Modules/Platform/Apple-GNU.cmake   | 5 +----
 Modules/Platform/Apple-Intel.cmake | 5 +----
 Modules/Platform/Apple-PGI.cmake   | 5 +----
 4 files changed, 4 insertions(+), 16 deletions(-)

diff --git a/Modules/Platform/Apple-Clang.cmake b/Modules/Platform/Apple-Clang.cmake
index 70fc75e9d5..0681bfb059 100644
--- a/Modules/Platform/Apple-Clang.cmake
+++ b/Modules/Platform/Apple-Clang.cmake
@@ -3,10 +3,7 @@
 
 
 # This module is shared by multiple languages; use include blocker.
-if(__APPLE_COMPILER_CLANG)
-  return()
-endif()
-set(__APPLE_COMPILER_CLANG 1)
+include_guard()
 
 macro(__apple_compiler_clang lang)
   set(CMAKE_${lang}_VERBOSE_FLAG "-v -Wl,-v") # also tell linker to print verbose output
diff --git a/Modules/Platform/Apple-GNU.cmake b/Modules/Platform/Apple-GNU.cmake
index 9985dddd7d..0eb8168310 100644
--- a/Modules/Platform/Apple-GNU.cmake
+++ b/Modules/Platform/Apple-GNU.cmake
@@ -3,10 +3,7 @@
 
 
 # This module is shared by multiple languages; use include blocker.
-if(__APPLE_COMPILER_GNU)
-  return()
-endif()
-set(__APPLE_COMPILER_GNU 1)
+include_guard()
 
 macro(__apple_compiler_gnu lang)
   set(CMAKE_${lang}_VERBOSE_FLAG "-v -Wl,-v") # also tell linker to print verbose output
diff --git a/Modules/Platform/Apple-Intel.cmake b/Modules/Platform/Apple-Intel.cmake
index 9f92d9592a..2d4f7e5917 100644
--- a/Modules/Platform/Apple-Intel.cmake
+++ b/Modules/Platform/Apple-Intel.cmake
@@ -3,10 +3,7 @@
 
 
 # This module is shared by multiple languages; use include blocker.
-if(__APPLE_COMPILER_INTEL)
-  return()
-endif()
-set(__APPLE_COMPILER_INTEL 1)
+include_guard()
 
 macro(__apple_compiler_intel lang)
   set(CMAKE_${lang}_VERBOSE_FLAG "-v -Wl,-v") # also tell linker to print verbose output
diff --git a/Modules/Platform/Apple-PGI.cmake b/Modules/Platform/Apple-PGI.cmake
index a68c08dea7..8d343b7d16 100644
--- a/Modules/Platform/Apple-PGI.cmake
+++ b/Modules/Platform/Apple-PGI.cmake
@@ -2,10 +2,7 @@
 # file Copyright.txt or https://cmake.org/licensing for details.
 
 # This module is shared by multiple languages; use include blocker.
-if(__APPLE_COMPILER_PGI)
-  return()
-endif()
-set(__APPLE_COMPILER_PGI 1)
+include_guard()
 
 macro(__apple_compiler_pgi lang)
   set(CMAKE_${lang}_OSX_COMPATIBILITY_VERSION_FLAG "-Wl,-compatibility_version,")