Merge pull request #2865 from BioDataAnalysis/emmenlau_minor_clangcl_…

…improvement

Separated MSVC and clang-cl settings for Windows

build/cmake/DefinePlatformSpecifc.cmake

@@ -25,8 +25,12 @@ set(CMAKE_DEBUG_POSTFIX "d" CACHE STRING "Set debug library postfix")
 
 # basic options
 foreach(lang IN ITEMS C CXX)
-  if("CMAKE_${lang}_COMPILER_ID" STREQUAL "MSVC" OR "${CMAKE_${lang}_SIMULATE_ID}" STREQUAL "MSVC")
+  if("CMAKE_${lang}_COMPILER_ID" STREQUAL "MSVC")
+    # These flags are not supported (or needed) with Clang-Cl on Windows:
     set(CMAKE_${lang}_FLAGS "${CMAKE_${lang}_FLAGS} /MP") # parallel build
+  endif()
+
+  if("CMAKE_${lang}_COMPILER_ID" STREQUAL "MSVC" OR "${CMAKE_${lang}_SIMULATE_ID}" STREQUAL "MSVC")
     set(CMAKE_${lang}_FLAGS "${CMAKE_${lang}_FLAGS} /W3") # warning level 3
     include(CheckCXXCompilerFlag)
     set(CMAKE_REQUIRED_QUIET ON)