ci: Rename variable CMake_SKIP_INSTALL to CMAKE_CI_NO_INSTALL

The latter follows our convention for other variable names.

.gitlab/ci/ctest_build.cmake

@@ -37,7 +37,7 @@ if ("$ENV{CTEST_NO_WARNINGS_ALLOWED}" AND num_warnings GREATER 0)
     "Found ${num_warnings} warnings (treating as fatal).")
 endif ()
 
-if (NOT "$ENV{CMake_SKIP_INSTALL}")
+if (NOT "$ENV{CMAKE_CI_NO_INSTALL}")
   ctest_build(APPEND
     TARGET install
     RETURN_VALUE install_result)

.gitlab/os-linux.yml

@@ -57,7 +57,7 @@
     variables:
         CMAKE_CONFIGURATION: debian10_iwyu
         CTEST_NO_WARNINGS_ALLOWED: 1
-        CMake_SKIP_INSTALL: 1
+        CMAKE_CI_NO_INSTALL: 1
 
 .debian10_aarch64:
     image: "kitware/cmake:ci-debian10-aarch64-2022-02-21"
@@ -83,7 +83,7 @@
     variables:
         CMAKE_CONFIGURATION: fedora35_tidy
         CTEST_NO_WARNINGS_ALLOWED: 1
-        CMake_SKIP_INSTALL: 1
+        CMAKE_CI_NO_INSTALL: 1
 
 .fedora35_clang_analyzer:
     extends: .fedora35
@@ -92,7 +92,7 @@
         CMAKE_CONFIGURATION: fedora35_clang_analyzer
         CMAKE_CI_BUILD_TYPE: Debug
         CTEST_NO_WARNINGS_ALLOWED: 1
-        CMake_SKIP_INSTALL: 1
+        CMAKE_CI_NO_INSTALL: 1
 
 .fedora35_sphinx:
     extends: .fedora35
@@ -101,7 +101,7 @@
         CMAKE_CONFIGURATION: fedora35_sphinx
         CTEST_NO_WARNINGS_ALLOWED: 1
         CTEST_SOURCE_SUBDIRECTORY: "Utilities/Sphinx"
-        CMake_SKIP_INSTALL: 1
+        CMAKE_CI_NO_INSTALL: 1
 
 .fedora35_sphinx_package:
     extends: .fedora35

.gitlab/os-macos.yml

@@ -52,7 +52,7 @@
     variables:
         CMAKE_CONFIGURATION: macos_package
         CTEST_NO_WARNINGS_ALLOWED: 1
-        CMake_SKIP_INSTALL: 1
+        CMAKE_CI_NO_INSTALL: 1
 
 .macos10.10_package:
     extends: .macos_build
@@ -60,7 +60,7 @@
     variables:
         CMAKE_CONFIGURATION: macos10.10_package
         CTEST_NO_WARNINGS_ALLOWED: 1
-        CMake_SKIP_INSTALL: 1
+        CMAKE_CI_NO_INSTALL: 1
 
 ### External testing