[gegl] tests: Silence -Wimplicit-function-declaration

[Debarshi Ray <debarshir src gnome org>]

commit 7cb72e3a9ade11a506e252623bead17635de2047
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Mar 20 10:57:51 2017 +0100

    tests: Silence -Wimplicit-function-declaration

 tests/simple/test-buffer-sharing.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/tests/simple/test-buffer-sharing.c b/tests/simple/test-buffer-sharing.c
index b80a86d..245f089 100644
--- a/tests/simple/test-buffer-sharing.c
+++ b/tests/simple/test-buffer-sharing.c
@@ -16,6 +16,7 @@
  */
 
 #include <gegl.h>
+#include <glib/gstdio.h>
 
 // in order of progression
 typedef enum _TestState {