fixed android zlib compile error.

CMakeLists.txt

@@ -233,7 +233,7 @@ ENDIF()
 if (IOS)
     set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS}   -fembed-bitcode -O3")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fembed-bitcode -O3")
-endif(IOS)
+endif()
 
 if (ASSIMP_COVERALLS)
     MESSAGE(STATUS "Coveralls enabled")

contrib/zlib/zlib.h

@@ -77,8 +77,9 @@ extern "C" {
   the consistency of the compressed data, so the library should never crash
   even in the case of corrupted input.
 */
+
 #ifdef __ANDROID__
-using zcrc_t = unsigned_long; 
+typedef unsigned long zcrc_t;
 #endif
 
 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));