compiler: fix stale comment in lexer

    
    Remove stale comment in code that accepts "go:nowritebarrier"
    pragma. Update comment for "go:nowritebarrierrec".
    
    Reviewed-on: https://go-review.googlesource.com/46416

From-SVN: r249564

gcc/go/gofrontend/MERGE

-8804c912363320e0c229c5a471fb6f4b9e5965e6
+54d83c2d67c35ad4f622936d2fbf81c17354fff9
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/lex.cc

@@ -1909,7 +1909,6 @@ Lex::skip_cpp_comment()
       // Applies to the next function.  If the function needs to use
       // any write barriers, it should emit an error instead.
       // FIXME: Should only work when compiling the runtime package.
-      // FIXME: Not implemented.
       this->pragmas_ |= GOPRAGMA_NOWRITEBARRIER;
     }
   else if (verb == "go:nowritebarrierrec")
@@ -1918,7 +1917,7 @@ Lex::skip_cpp_comment()
       // function that it calls, needs to use any write barriers, it
       // should emit an error instead.
       // FIXME: Should only work when compiling the runtime package.
-      // FIXME: Not implemented.
+      // FIXME: currently treated the same as go:nowritebarrier
       this->pragmas_ |= GOPRAGMA_NOWRITEBARRIERREC;
     }
   else if (verb == "go:cgo_unsafe_args")