[PATCH] Turn off uninitialized-use warnings for gcc in cmake build

[Chandler Carruth]

  If I can jump in...


================
Comment at: cmake/config-ix.cmake:320-322
@@ +319,5 @@
+  else()
+    # In older versions of gcc, the compiler flag check above will still pass
+    # for unsupported -W flags. In such cases, just use -Wno-uninitialized if
+    # available.
+    execute_process(COMMAND ${CMAKE_CXX_COMPILER} -dumpversion OUTPUT_VARIABLE GXX_VERSION)
----------------
So, why not test for -Wmaybe-uninitialized?

Many versions of GCC ignore -Wno-... flags they don't understand, but I think they're very rigorous about supporting a -Wno-... variant for every flag the support a -W... variant of, so test for the positive one.

My expected logic here is:

- If GCC
  - If -Wmaybe-uninitiaziled is supported, use -Wno-maybe-uninitialized
  - Else use -Wno-uninitialized


http://llvm-reviews.chandlerc.com/D353

BRANCH
  gcc_cmake_fix

ARCANIST PROJECT
  llvm