libstdc++: add missing __

I forgot the __ in my recent r15-3500-g1914ca8791ce4e.

libstdc++-v3/ChangeLog:

	* include/bits/regex_constants.h: Add __ to attribute.

diff --git a/libstdc++-v3/include/bits/regex_constants.h b/libstdc++-v3/include/bits/regex_constants.h
index 4148093bc4e05900074d6a8d42bf9b2375657dcd..cb70a8647d904e397230050b491a85e8ac6de4c0 100644 (file)
--- a/libstdc++-v3/include/bits/regex_constants.h
+++ b/libstdc++-v3/include/bits/regex_constants.h
@@ -66,7 +66,7 @@ namespace regex_constants
    * elements @c ECMAScript, @c basic, @c extended, @c awk, @c grep, @c egrep
    * %set.
    */
-  enum [[gnu::flag_enum]] syntax_option_type : unsigned int
+  enum [[__gnu__::__flag_enum__]] syntax_option_type : unsigned int
   {
     _S_icase           = 1 << 0,
     _S_nosubs          = 1 << 1,