[Frontend] Factor out helper function, for clarity.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173853 91177308-0d34-0410-b5e6-96231b3b80d8
[Frontend] Rename a member variable to clarify its intent.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173854 91177308-0d34-0410-b5e6-96231b3b80d8
[Frontend] Make the include dir group independent from the "use sysroot" bit.

 - This slightly decouples the path handling, since before the group sometimes
   dominated the "use sysroot" bit, but it was still passed in via the API.

 - No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173855 91177308-0d34-0410-b5e6-96231b3b80d8
Removed couple of html named character references in
my last patch.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173856 91177308-0d34-0410-b5e6-96231b3b80d8
[Frontend] Add an ExternCSystem include entry group.

 - The only group where it makes sense for the "ExternC" bit is System, so this
   simplifies having to have the extra isCXXAware (or ImplicitExternC, depending
   on what code you talk to) bit caried around.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173859 91177308-0d34-0410-b5e6-96231b3b80d8
[Frontend] Remove actual ImplicitExternC member variable.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173860 91177308-0d34-0410-b5e6-96231b3b80d8
clang/test/Driver/asan-ld.c: Try not to mismatch temporary file, like "tmpkcfdld".

If we had the regular expression "\b" in FileCheck like Perl...

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173861 91177308-0d34-0410-b5e6-96231b3b80d8
[Frontend] Remove HeaderSearchOptions::Entry::IsInternal, which is unused.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173866 91177308-0d34-0410-b5e6-96231b3b80d8