Split AddDefaultSystemIncludePaths into C, C++ and framework specific functions.

The user visible changes are:

*) Frameworks are only searched on OS X
*) The Cygwin c++ headers are now marked as c++ aware. I am almost
sure that not marking them was a bug.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@85240 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed