Restore --no-lines.

Reported by Jim Kent.
* data/c.m4 (b4_syncline): New.
* data/glr.c, data/yacc.c, data/lalr1.cc: Use it.
* src/reader.c (prologue_augment, epilogue_set): Use b4_syncline.
* src/output.c (user_actions_output): Likewise.
(prepare): Define 'b4_synclines_flag'.

src/muscle_tab.c

@@ -65,12 +65,6 @@ muscle_init (void)
   /* Version and input file.  */
   MUSCLE_INSERT_STRING ("version", VERSION);
   MUSCLE_INSERT_STRING ("filename", infile);
-
-  /* FIXME: there should probably be no default here, only in the
-     skeletons.  */
-
-  /* Default #line formatting.  */
-  MUSCLE_INSERT_STRING ("linef", "#line %d %s\n");
 }