LLVM_BUILD_32_BITS: Add -m32 with CMAKE_C*_FLAGS. [CMP0056]
LLVM_BUILD_32_BITS: Add -m32 with CMAKE_C*_FLAGS. [CMP0056]

With CMP0056, try_compile() uses also CMAKE_EXE_LINKER_FLAG.
It caused mismatch between CMAKE_CXX_FLAGS and CMAKE_EXE_LINKER_FLAGS, to fail to examine CXX_SUPPORTS_CXX11 with -m32.

FYI, before this, try_compile() tries without -m32 regardless of LLVM_BUILD_32_BITS.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@271871 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm