Frontend: Teach clang -cc1as to respond to -v.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@114863 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Driver/CC1AsOptions.td

@@ -46,6 +46,7 @@ def _help : Flag<"--help">, Alias<help>;
 def version : Flag<"-version">,
   HelpText<"Print the assembler version">;
 def _version : Flag<"--version">, Alias<version>;
+def v : Flag<"-v">, Alias<version>;
 
 // Generic forwarding to LLVM options. This should only be used for debugging
 // and experimental features.