ObjC: Add OBJC/OBJCXX flags to Xcode projects

Fixes: #19936

Tests/RunCMake/XcodeProject/RunCMakeTest.cmake

@@ -54,6 +54,20 @@ endfunction()
 
 XcodeDependOnZeroCheck()
 
+function(XcodeObjcxxFlags testName)
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/${testName}-build)
+  set(RunCMake_TEST_NO_CLEAN 1)
+
+  file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+  file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+
+  run_cmake(${testName})
+  run_cmake_command(${testName}-build ${CMAKE_COMMAND} --build .)
+endfunction()
+
+XcodeObjcxxFlags(XcodeObjcFlags)
+XcodeObjcxxFlags(XcodeObjcxxFlags)
+
 # Isolate device tests from host architecture selection.
 unset(ENV{CMAKE_OSX_ARCHITECTURES})
 

Tests/RunCMake/XcodeProject/XcodeObjcFlags.cmake

@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.15)
+project(objctest LANGUAGES C OBJC)
+
+include(CheckOBJCCompilerFlag)
+check_objc_compiler_flag(-fobjc-arc HAVE_OBJC_ARC)
+
+if(HAVE_OBJC_ARC)
+  add_compile_options(-fobjc-arc)
+  add_compile_definitions(HAVE_OBJC_ARC)
+endif()
+
+add_library(myfuncs STATIC myfuncs.m)

Tests/RunCMake/XcodeProject/XcodeObjcxxFlags.cmake

@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.15)
+project(objcxxtest LANGUAGES CXX OBJCXX)
+
+include(CheckOBJCXXCompilerFlag)
+check_objcxx_compiler_flag(-fobjc-arc HAVE_OBJC_ARC)
+
+if(HAVE_OBJC_ARC)
+  add_compile_options(-fobjc-arc)
+  add_compile_definitions(HAVE_OBJC_ARC)
+endif()
+
+add_library(myfuncs STATIC myfuncs.mm)

Tests/RunCMake/XcodeProject/myfuncs.m

@@ -0,0 +1,3 @@
+#if defined(HAVE_OBJC_ARC) && ! __has_feature(objc_arc)
+#error THIS CODE MUST BE COMPILED WITH ARC ENABLED!
+#endif

Tests/RunCMake/XcodeProject/myfuncs.mm

@@ -0,0 +1,3 @@
+#if defined(HAVE_OBJC_ARC) && ! __has_feature(objc_arc)
+#error THIS CODE MUST BE COMPILED WITH ARC ENABLED!
+#endif