Fix Undefined Symbol _ftelli64 (#2319)

Author: audinue

src/external/cgltf.h

@@ -948,7 +948,11 @@ static cgltf_result cgltf_default_file_read(const struct cgltf_memory_options* m
 		fseek(file, 0, SEEK_END);
 
 #ifdef _WIN32
-		__int64 length = _ftelli64(file);
+		#ifdef __TINYC__ 
+			__int64 length = ftell(file);
+		#else
+			__int64 length = _ftelli64(file);
+		#endif
 #else
 		long length = ftell(file);
 #endif