This project provides a version of the JavaNativeFoundation framework compiled both for x86-64 and the M1 arm64 architecture.
As there is no arm64 definition for the JavaNativeFramework it is not possible to cross compile jni-libraries for M1 macs.
(See this relevant thread)
You can either include the framework directly or just use it as a drop in replacement for the linker during cross compilation on non arm macs.
If you only use the framwork for linking then you also need to specify the following linker options to ensure that the dynamic library is loaded
from the system framework path. Otherwise linking will fail as macOS can't find the JNF dynamic library relative to your library.
-rpath /System/Library/Frameworks/JavaVM.framework/Versions/A/Frameworks/
-rpath /System/Library/Frameworks/
The framework is compiled directly from the apple openjdk port.