[CMake] Effectively revert r230683.
[CMake] Effectively revert r230683.

Clang in 32-bit mode may choose to target different architecture
than host compiler.

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@230709 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt