stop searching GCC install directories for standard C headers (but keep searching for C++ headers when in C++ mode).  In theory clang should be able to find all of its own headers now.  If not, the CPATH or C_INCLUDE_PATH environment variables can be specified to add a include path.
stop searching GCC install directories for standard C headers (but
keep searching for C++ headers when in C++ mode).  In theory clang
should be able to find all of its own headers now.  If not, the
CPATH or C_INCLUDE_PATH environment variables can be specified to
add a include path.


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@64862 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang