Embed bitcode in object file (clang cc1 part)

Summary:
Teach clang to embed bitcode inside bitcode. When -fembed-bitcode cc1
option is used, clang will embed both the input bitcode and cc1
commandline into the bitcode in special sections before compiling to
the object file.  Using -fembed-bitcode-marker will only introduce a
marker in both sections.

Depends on D17390

Reviewers: rsmith

Subscribers: yaron.keren, vsk, cfe-commits

Differential Revision: http://reviews.llvm.org/D17392

llvm-svn: 269202