mkdir: fix -p on FreeBSD

This patch is libbb.make_directory.diff from Debian kFreeBSD at:
http://svn.debian.org/viewsvn/d-i/people/slackydeb/kfreebsd/busybox/1.14/debian

Signed-off-by: Jeremie Koenig <jk@jk.fr.eu.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

libbb/make_directory.c

@@ -86,7 +86,7 @@ int FAST_FUNC bb_make_directory(char *path, long mode, int flags)
 		if (mkdir(path, 0777) < 0) {
 			/* If we failed for any other reason than the directory
 			 * already exists, output a diagnostic and return -1 */
-			if (errno != EEXIST
+			if ((errno != EEXIST && errno != EISDIR)
 			 || !(flags & FILEUTILS_RECUR)
 			 || ((stat(path, &st) < 0) || !S_ISDIR(st.st_mode))
 			) {