https://github.com/linkotec/ffts
https://github.com/ValveSoftware/ffts
Sorry, but I haven't been able to touch this for many years!
To build for Android, edit and run build_android.sh
To build for iOS, edit and run build_iphone.sh
To build for Linux or OS X on x86, run ./configure --enable-sse --enable-single --prefix=/usr/local make make install
Optionally build for Windows and Linux with CMake, run mkdir build cd build cmake ..
FFTS dynamically generates code at runtime. This can be disabled with --disable-dynamic-code
Note that 32 bit x86 dynamic machine code generation is not supported at the moment.
For JNI targets: --enable-jni will build the jni stuff automatically for the host target, and --enable-shared must also be added manually for it to work.