Remove __ARGS macro. Close #205

This is a squash of all commits sent to #81.

- Remove unused undef of __ARGS.
- Fix mch_rename declaration.
- Follow changes related to moved & extracted files.
- Properly indent function declarations of getchar.h and quickfix.c.

src/if_cscope_defs.h

@@ -37,7 +37,7 @@
 
 typedef struct {
   char *  name;
-  int (*func)__ARGS((exarg_T *eap));
+  int (*func)(exarg_T *eap);
   char *  help;
   char *  usage;
   int cansplit;                 /* if supports splitting window */