--- a/Source/ZLib/gzguts.h
+++ b/Source/ZLib/gzguts.h
@@ -26,6 +26,10 @@
# include <limits.h>
#endif
+#ifdef __ANDROID__
+# include <unistd.h>
+#endif
+
#ifndef _POSIX_SOURCE
# define _POSIX_SOURCE