[libcxx][libcxxabi] Remove the unused CMake checks

These seemed to have been used in the past but were since removed
by the add_compile_flags_if_supported functions that combine these
these checks and adding the flag, but the original checks were never
removed.

Differential Revision: https://reviews.llvm.org/D62566

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@362058 91177308-0d34-0410-b5e6-96231b3b80d8

cmake/config-ix.cmake

@@ -76,15 +76,6 @@ if(NOT WIN32 OR MINGW)
   include(CheckLibcxxAtomic)
 endif()
 
-# Check compiler flags
-
-check_cxx_compiler_flag(/WX                     LIBCXX_HAS_WX_FLAG)
-check_cxx_compiler_flag(/WX-                    LIBCXX_HAS_NO_WX_FLAG)
-check_cxx_compiler_flag(/EHsc                   LIBCXX_HAS_EHSC_FLAG)
-check_cxx_compiler_flag(/EHs-                   LIBCXX_HAS_NO_EHS_FLAG)
-check_cxx_compiler_flag(/EHa-                   LIBCXX_HAS_NO_EHA_FLAG)
-check_cxx_compiler_flag(/GR-                    LIBCXX_HAS_NO_GR_FLAG)
-
 # Check libraries
 if(WIN32 AND NOT MINGW)
   # TODO(compnerd) do we want to support an emulation layer that allows for the