elf: Add #include <errno.h> for use of E* constants.

In __strerror_r we use errno constants and must include errno.h.

Tested on x86_64 and i686 without regression.

elf/dl-minimal.c

@@ -25,7 +25,7 @@
 #include <dl-minimal-malloc.h>
 #include <stdio.h>
 #include <unistd.h>
-
+#include <errno.h>
 
 /* The rtld startup code calls __rtld_malloc_init_stubs after the
   first self-relocation to adjust the pointers to the minimal