dont override PATH_MAX, include limits.h

Signed-off-by: Christoph Lohmann <20h@r-36.net>

md2point.c

@@ -2,13 +2,12 @@
  * See LICENSE for license details.
  */
 #include <unistd.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <err.h>
 #include <string.h>
 
-#define PATH_MAX 128
-
 char buf[PATH_MAX];
 
 /* from git://bitreich.org/utf8expr */