[CMake] Adding some missing CMake includes. NFC.
[CMake] Adding some missing CMake includes. NFC.

This happens to be working now because the includes exist in another CMake file that is included before this one. That will change with upcoming refactoring.

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@267912 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