Revert "build: improve the builds with Visual Studio"

This reverts commit d9dde28.

Author: stephentyrone

cmake/modules/ClangClCompileRules.cmake

@@ -1,10 +1,8 @@
 
 # clang-cl interprets paths starting with /U as macro undefines, so we need to
 # put a -- before the input file path to force it to be treated as a path.
-if(NOT MSVC AND "${CMAKE_SIMULATE_ID}" STREQUAL "MSVC")
-  string(REPLACE "-c <SOURCE>" "-c -- <SOURCE>" CMAKE_C_COMPILE_OBJECT "${CMAKE_C_COMPILE_OBJECT}")
-  string(REPLACE "-c <SOURCE>" "-c -- <SOURCE>" CMAKE_CXX_COMPILE_OBJECT "${CMAKE_CXX_COMPILE_OBJECT}")
-endif()
+string(REPLACE "-c <SOURCE>" "-c -- <SOURCE>" CMAKE_C_COMPILE_OBJECT "${CMAKE_C_COMPILE_OBJECT}")
+string(REPLACE "-c <SOURCE>" "-c -- <SOURCE>" CMAKE_CXX_COMPILE_OBJECT "${CMAKE_CXX_COMPILE_OBJECT}")
 
 # NOTE(compnerd) incremental linking is known to cause corruption in the
 # protocol conformance tables.  Avoid using incremental links with Visual

cmake/modules/SwiftSharedCMakeConfig.cmake

@@ -258,11 +258,7 @@ endmacro()
 macro(swift_common_cxx_warnings)
   # Make unhandled switch cases be an error in assert builds
   if(DEFINED LLVM_ENABLE_ASSERTIONS)
-    check_cxx_compiler_flag("-Werror=switch" CXX_SUPPORTS_WERROR_SWITCH_FLAG)
-    append_if(CXX_SUPPORTS_WERROR_SWITCH_FLAG "-Werror=switch" CMAKE_CXX_FLAGS)
-
-    check_cxx_compiler_flag("/we4062" CXX_SUPPORTS_WE4062)
-    append_if(CXX_SUPPORTS_WE4062 "/we4062" CMAKE_CXX_FLAGS)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror=switch")
   endif()
 
   check_cxx_compiler_flag("-Werror -Wdocumentation" CXX_SUPPORTS_DOCUMENTATION_FLAG)