This change is the third of 3 patches to add support for specifying
the profile output from the command line via -fprofile-instr-generate=<path>,
where the specified output path/file will be overridden by the
LLVM_PROFILE_FILE environment variable.
This patch adds the necessary support to the clang frontend, and adds a
new test.
The compiler-rt and llvm parts are r236055 and r236288, respectively.
Patch by Teresa Johnson. Thanks!
llvm-svn: 236289