Apply paxed's DEBUG patch to remove DEBUG/D_DEBUG.

Move debugging output into couple preprocessor defines, which
    are no-op without DEBUG.  To show debugging output from a
    certain source files, use sysconf:

    DEBUGFILES=dungeon.c questpgr.c

    Also fix couple debug lines which did not compile.

This also includes fixes due to Derek Ray to depugpline to work better
on other platforms.

src/shk.c

@@ -5,8 +5,6 @@
 
 #include "hack.h"
 
-/*#define DEBUG*/
-
 #define PAY_SOME    2
 #define PAY_BUY     1
 #define PAY_CANT    0	/* too poor */
@@ -1207,9 +1205,7 @@ dopay()
 	}
 
 	if(!shkp) {
-#ifdef DEBUG
-		pline("dopay: null shkp.");
-#endif
+		debugpline("dopay: null shkp.");
 		return(0);
 	}
 proceed: