Adding the required c flag to compile zip files using gcc 4.9

code/CMakeLists.txt

@@ -1137,6 +1137,9 @@ ELSE()
   TARGET_COMPILE_OPTIONS(assimp PRIVATE -Werror)
 ENDIF()
 
+# adds C_FLAGS required to compile zip.c on old GCC 4.x compiler
+TARGET_COMPILE_FEATURES(assimp PUBLIC c_std_99)
+
 TARGET_INCLUDE_DIRECTORIES ( assimp PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../include>
   $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/../include>