improve compatibility with GCC: when generating the ".d" filename to use

and the filename has multiple .'s in it, use the last.  For example, "foo.bar.cpp"
should produce "foo.bar.d" not "foo.d".  Patch by Johan Boule in PR8391


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123576 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Driver/Tools.cpp

@@ -1964,7 +1964,7 @@ const char *darwin::CC1::getBaseInputStem(const ArgList &Args,
                                           const InputInfoList &Inputs) {
   const char *Str = getBaseInputName(Args, Inputs);
 
-  if (const char *End = strchr(Str, '.'))
+  if (const char *End = strrchr(Str, '.'))
     return Args.MakeArgString(std::string(Str, End));
 
   return Str;