[driver] Create a new L_Group for language options and add the -std= option to
said group.  Also classify the group as a CompileOnly_Group so that this option
does not cause an unused argument warning when used with a link command.
rdar://11153013


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153763 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 6bc0a7d..97872f7 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -21,6 +21,7 @@
 def CompileOnly_Group     : OptionGroup<"<CompileOnly group>">;
 
 def I_Group               : OptionGroup<"<I group>">, Group<CompileOnly_Group>;
+def L_Group               : OptionGroup<"<L group>">, Group<CompileOnly_Group>;
 def M_Group               : OptionGroup<"<M group>">, Group<CompileOnly_Group>;
 def T_Group               : OptionGroup<"<T group>">;
 def O_Group               : OptionGroup<"<O group>">, Group<CompileOnly_Group>;
@@ -765,7 +766,7 @@
 def static_libstdcxx : Flag<"-static-libstdc++">;
 def static : Flag<"-static">, Flags<[NoArgumentUnused]>;
 def std_default_EQ : Joined<"-std-default=">;
-def std_EQ : Joined<"-std=">;
+def std_EQ : Joined<"-std=">, Group<L_Group>;
 def stdlib_EQ : Joined<"-stdlib=">;
 def sub__library : JoinedOrSeparate<"-sub_library">;
 def sub__umbrella : JoinedOrSeparate<"-sub_umbrella">;