Merge topic 'IntelLLVM-no-imsvc' into release-3.20

e5563e59 IntelLLVM: Remove unsupported -imsvc system include flag

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !5795

Modules/Compiler/IntelLLVM.cmake

@@ -18,7 +18,6 @@ set(__pch_header_OBJCXX "objective-c++-header")
 if(CMAKE_HOST_WIN32)
   # MSVC-like
   macro(__compiler_intel_llvm lang)
-    set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-imsvc ")
     if(NOT "x${lang}" STREQUAL "xFortran")
       set(CMAKE_${lang}_COMPILE_OPTIONS_INVALID_PCH -Winvalid-pch)
     endif()