ash_test: printenv: fix missing includes

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/shell/ash_test/printenv.c b/shell/ash_test/printenv.c
index c4ccda8..c0c5e19 100644
--- a/shell/ash_test/printenv.c
+++ b/shell/ash_test/printenv.c
@@ -24,6 +24,7 @@
    with Bash; see the file COPYING.  If not, write to the Free Software
    Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
 
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>