Make this compile with DEBUG defined now that WARNS=0 has been removed

from the Makefile:
- Print pointers with %p instead of %x.
- Include missing headers to get prototypes.

Noticed by:	benno

bin/sh/eval.c

@@ -580,7 +580,7 @@ evalbackcmd(union node *n, struct backcmd *result)
 	}
 out:
 	popstackmark(&smark);
-	TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n",
+	TRACE(("evalbackcmd done: fd=%d buf=%p nleft=%d jp=%p\n",
 		result->fd, result->buf, result->nleft, result->jp));
 }
 

bin/sh/jobs.c

@@ -982,7 +982,7 @@ dowait(int block, struct job *job)
 				showjob(thisjob, pid, 0, 0);
 		}
 	} else {
-		TRACE(("Not printing status, rootshell=%d, job=0x%x\n", rootshell, job));
+		TRACE(("Not printing status, rootshell=%d, job=%p\n", rootshell, job));
 		if (thisjob)
 			thisjob->changed = 1;
 	}

bin/sh/show.c

@@ -42,7 +42,9 @@ static char sccsid[] = "@(#)show.c	8.3 (Berkeley) 5/4/95";
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <fcntl.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <stdarg.h>
 #include <errno.h>