diff --git a/src/dep/libs/libspng/spng.c b/src/dep/libs/libspng/spng.c
index c1f0e7e036..86985842a3 100644
--- a/src/dep/libs/libspng/spng.c
+++ b/src/dep/libs/libspng/spng.c
@@ -10,7 +10,12 @@
 #include <math.h>
 
 #define ZLIB_CONST
-#define SPNG_DISABLE_OPT
+
+#ifdef __GNUC__
+  #if __GNUC__ < 6
+    #define SPNG_DISABLE_OPT
+  #endif
+#endif
 
 #ifdef __FRAMAC__
     #define SPNG_DISABLE_OPT
@@ -19,7 +24,7 @@
     #ifdef SPNG_USE_MINIZ
         #include <miniz.h>
     #else
-        #include <zlib.h>
+        #include "zlib.h"
     #endif
 #endif