Add missing includes for fprintf()

src/init.c:118:9: warning: incompatible implicit declaration of built-in
function 'fprintf' [enabled by default]
         fprintf(stderr, "Error in auto_init()\n");
         ^

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Norbert Pocs <npocs@redhat.com>

src/buffer.c

@@ -26,6 +26,7 @@
 #include <limits.h>
 #include <stdarg.h>
 #include <stdbool.h>
+#include <stdio.h>
 
 #ifndef _WIN32
 #include <netinet/in.h>