More minor cosmetic improvements:

- remove another senseless "extern" keyword that was applied to a
function definition
- change a foo more function signatures from "some_type foo()" to
"some_type foo(void)"
- rewrite another K&R style function definition
- make the type of the "action" function pointer in the KeyWord struct
in src/backend/utils/adt/formatting.c more precise

src/interfaces/ecpg/preproc/output.c

@@ -3,7 +3,7 @@
 #include "extern.h"
 
 void
-output_line_number()
+output_line_number(void)
 {
 	if (input_filename)
 		fprintf(yyout, "\n#line %d \"%s\"\n", yylineno, input_filename);