Assimp Android LTS NDK 23 Fix

contrib/unzip/crypt.h

@@ -17,8 +17,10 @@
 #define _MINICRYPT_H
 
 #if ZLIB_VERNUM < 0x1270
+#if !defined(Z_U4)
 typedef unsigned long z_crc_t;
 #endif
+#endif
 
 #ifdef __cplusplus
 extern "C" {