Also handle the output file (--verbose) with obstacks.

* files.c (foutput): Remove.
(output_obstack): New.
Adjust all dependencies.
* src/conflicts.c: Return a string.
* src/system.h (obstack_grow_string): Rename as...
(obstack_sgrow): this.  Be ready to work with non literals.
(obstack_fgrow4): New.

src/files.h

@@ -37,10 +37,6 @@ extern char *spec_file_prefix;
 /* Read grammar specifications. */
 extern FILE *finput;
 
-/* Optionally output messages describing the actions taken. */
-extern FILE *foutput;
-
-
 /* Output all the action code; precise form depends on which parser. */
 extern struct obstack action_obstack;
 
@@ -57,6 +53,9 @@ extern struct obstack attrs_obstack;
 /* ... and output yyguard, containing all the guard code. */
 extern struct obstack guard_obstack;
 
+/* The verbose output. */
+extern struct obstack output_obstack;
+
 
 extern char *infile;
 extern char *attrsfile;