[cmake] Support enabling -Werror in the OpenMP runtime CMake build and
clean up the build.

This disables all of the Clang warnings that fire for me when building
libomp.so on Linux with a recent Clang binary. Lots of these should
probably be fixed, but I want to at least get the build warning-clean
and make it easy to keep that way.

I also switched a bunch of the warnings that are used both for C and C++
compiles to check the flag with C compilation test.

Differential Revision: http://reviews.llvm.org/D11253

llvm-svn: 242604
GitOrigin-RevId: 5145156a4a7aa1aba6fe051be8615813541aa0e7
3 files changed
tree: f23aac496f9a4782d3ca9c0480c61fb625b4d9a7
  1. offload/
  2. runtime/
  3. testsuite/
  4. www/
  5. CMakeLists.txt
  6. CREDITS.txt
  7. LICENSE.txt