Forward -u to the linker on gnutools toolchains

Summary:
The BSDs and Darwin all forward the whole 'u' group, but gcc only
forwards -u so far as I can tell.  I only forward -u, since that's a
minimal change, and many people object to magically recognizing and
forwarding linker arguments.

Reviewers: chandlerc, joerg

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4304

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211756 91177308-0d34-0410-b5e6-96231b3b80d8
RAV: visit copy expressions of captured variables in blocks (ObjC++11)

Patch by Mathieu Baudet.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211758 91177308-0d34-0410-b5e6-96231b3b80d8
Reformat RAVs to sync up following recent updates

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211759 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGen: Improve warnings about uninstrumented files when profiling

Improve the warning when building with -fprofile-instr-use and a file
appears not to have been profiled at all. This keys on whether a
function is defined in the main file or not to avoid false negatives
when one includes a header with functions that have been profiled.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211760 91177308-0d34-0410-b5e6-96231b3b80d8