Merge topic 'check-compiler-flag-result' into release-3.18

d4390c13 Merge branch 'backport-3.17-check-compiler-flag-result'
d4659091 Check*CompilerFlag: Do not set result as a normal variable too

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Alexander Grund <github@grundis.de>
Merge-request: !5250

Modules/CheckCCompilerFlag.cmake

@@ -54,5 +54,4 @@ function(check_c_compiler_flag _flag _var)
   foreach(v IN LISTS _locale_vars)
     set(ENV{${v}} ${_locale_vars_saved_${v}})
   endforeach()
-  set(${_var} "${${_var}}" PARENT_SCOPE)
 endfunction()

Modules/CheckCXXCompilerFlag.cmake

@@ -54,5 +54,4 @@ function(check_cxx_compiler_flag _flag _var)
   foreach(v IN LISTS _locale_vars)
     set(ENV{${v}} ${_locale_vars_saved_${v}})
   endforeach()
-  set(${_var} "${${_var}}" PARENT_SCOPE)
 endfunction()