Include <stdlib.h>, <string.h> unconditionally.

(free): Remove decl.

lib/mountlist.c

@@ -21,18 +21,9 @@
 
 #include <stdio.h>
 #include <sys/types.h>
+#include <stdlib.h>
+#include <string.h>
 
-
-#ifdef STDC_HEADERS
-# include <stdlib.h>
-#else
-void free ();
-#endif
-#if defined STDC_HEADERS || defined HAVE_STRING_H
-# include <string.h>
-#else
-# include <strings.h>
-#endif
 #include "xalloc.h"
 
 #ifndef strstr