Fixed Android arm64 link error (#227)

Having this flag in the generated project files produces errors like this:

/Users/oliver/Library/Android/sdk/ndk/21.0.6113669/toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/lib/gcc/aarch64-linux-android/4.9.x/../../../../aarch64-linux-android/bin/ld: unrecognized option '--fix-cortex-a8'