[driver] Add follow up comment for r139551 to ensure the unused option is not

removed in the future.
rdar://10110352 and PR10908

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139602 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 5846c1b5f31011a4584b7712bb2f52fd28190400..d1040adfc9b1723573b6ee20c613592b080fbf27 100644 (file)
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -134,6 +134,8 @@ def ccc_ : Joined<"-ccc-">, Group<ccc_Group>, Flags<[Unsupported]>;
 
 def _HASH_HASH_HASH : Flag<"-###">, Flags<[DriverOption]>,
     HelpText<"Print the commands to run for this compilation">;
+// The '--' option is here for the sake of compatibility with gcc, but is 
+// being ignored by the driver.
 def _DASH_DASH : Flag<"--">, Flags<[DriverOption]>;
 def A : JoinedOrSeparate<"-A">;
 def B : JoinedOrSeparate<"-B">;