Honour DriverOnly for enum values in error messages

/gcc/ChangeLog

	* opts-common.c (read_cmdline_option): List DriverOnly enum values as
	valid only in the error message of the driver, not in the messages of
	the language compilers.

From-SVN: r226297

gcc/ChangeLog

+2015-07-28  Dominik Vogt  <vogt@linux.vnet.ibm.com>
+
+	* opts-common.c (read_cmdline_option): List DriverOnly enum values
+	as valid only in the error message of the driver, not in the
+	messages of the language compilers.
+
 2015-07-27  Tom de Vries  <tom@codesourcery.com>
 
 	* tree-parloops.c (gather_scalar_reductions): Simplify function

gcc/opts-common.c

@@ -1079,6 +1079,8 @@ read_cmdline_option (struct gcc_options *opts,
       p = s;
       for (i = 0; e->values[i].arg != NULL; i++)
 	{
+	  if (!enum_arg_ok_for_language (&e->values[i], lang_mask))
+	    continue;
 	  size_t arglen = strlen (e->values[i].arg);
 	  memcpy (p, e->values[i].arg, arglen);
 	  p[arglen] = ' ';