Make libqcompostprocbundle build with the VNDK.

When the vndk is enabled (BOARD_VNDK_VERSION=current),
vendor libraries must only link against vendor variants
in the build system. This means that they receive restricted
sets of headers and that automatic global headers are restricted.

Test: build libqcompostprocbundle with BOARD_VNDK_VERSION=current
Bug: 37342627
Change-Id: I213c4937f64e811d8018806982dc299c3e7e668a
diff --git a/post_proc/effect_api.c b/post_proc/effect_api.c
index 9c15e8f..37728db 100644
--- a/post_proc/effect_api.c
+++ b/post_proc/effect_api.c
@@ -17,8 +17,10 @@
 #define LOG_TAG "offload_effect_api"
 //#define LOG_NDEBUG 0
 
+#include <stdio.h>
 #include <errno.h>
 #include <stdbool.h>
+
 #include <cutils/log.h>
 #include <tinyalsa/asoundlib.h>
 #include <sound/audio_effects.h>