Add warning flag for '#import is a language extension', -W#import-pedantic.

Don't know if it is an anathema to include '#' in the warning name.  I'm fine
with changing it, but this was the most obvious name.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152886 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed