* src/output.c (output_skeleton): Don't disable M4sugar comments

too soon: it results in comments being expanded.
* data/yacc.c, data/glr.c, data/lalr1.cc: Do it right before the
first output.

data/glr.c

@@ -111,6 +111,8 @@ m4_define_default([b4_header_guard],
                                 [[^ABCDEFGHIJKLMNOPQRSTUVWXYZ]], [_])])
 
 
+# We do want M4 expansion after # for CPP macros.
+m4_changecom()
 m4_divert(0)dnl
 #output "b4_output_parser_name"
 b4_copyright([Skeleton parser for GLR parsing with Bison], [2002])

data/lalr1.cc

@@ -105,6 +105,8 @@ m4_define([b4_constructor],
 		    [])])
 
 
+# We do want M4 expansion after # for CPP macros.
+m4_changecom()
 m4_divert(0)dnl
 #output "b4_output_header_name"
 b4_copyright([C++ Skeleton parser for LALR(1) parsing with Bison],

data/yacc.c

@@ -156,7 +156,8 @@ m4_popdef([b4_dollar_dollar])dnl
 ])
 
 
-
+# We do want M4 expansion after # for CPP macros.
+m4_changecom()
 m4_divert(0)dnl
 #output "b4_output_parser_name"
 b4_copyright([Skeleton parser for Yacc-like parsing with Bison],