MFC r293014:

Merge r293006 from clang380-import branch:

For determining the compiler version, quote the string to be echo'd,
otherwise the command might fail. This is because clang -v now results
in the following:

FreeBSD clang version 3.8.0 (trunk 256633) (based on LLVM 3.8.0svn)

The second "3.8.8svn)" string tripped up the shell command.