Sorry for the late reply.
Using try-catch is un-recommended on android ndk. As you seen, cocos2d-x isn’t use it. Linking stlport is the right choice.
“isdigit(int)” is a method in standard C library, you can find it in android-ndk-r5/platforms/android-9/arch-arm/usr/include/ctype.h
ndk-build can find the ndk headers if you run the build commend at the root of android-ndk-r5
For example, your path is
Then you can run the build_native.sh in MyGame/android/ folder (don’t forget to modify the XXX_ROOT params in it),
or manually run
./ndk-build -C /MyProject/MyGame/android/ // run ndk-build at the root of ndk