Fix build on macOS Apple Silicon (darwin-aarch64)

[axgd-code]

Problem

Building libusb4java on macOS Apple Silicon (darwin-aarch64) fails at the link step with undefined symbols:

Undefined symbols for architecture arm64:
  _IOCreatePlugInInterfaceForService, referenced from:
      _usbi_backend in libusb-1.0.a(darwin_usb.c.o)
  _kIOMasterPortDefault, referenced from:
      _usbi_backend in libusb-1.0.a(darwin_usb.c.o)
  _objc_msgSend, referenced from:
      _usbi_backend in libusb-1.0.a(darwin_usb.c.o)
  ...
ld: symbol(s) not found for architecture arm64

This happens because the build script (dists/darwin/build) links libusb statically. The static libusb-1.0.a on macOS depends on Apple system frameworks (CoreFoundation, IOKit, Security) and the Objective-C runtime (objc), which are not automatically pulled in by CMake.

This issue was first reported in #12 and is also tracked upstream at usb4java/usb4java#86. It affects all Apple Silicon Macs (M1/M2/M3/M4) running macOS. Related discussion: marian-m12l/studio#244.

Fix

Add an APPLE-guarded block in src/CMakeLists.txt that links the required macOS system frameworks:

if(APPLE)
  target_link_libraries(usb4java
    "-framework CoreFoundation"
    "-framework IOKit"
    "-framework Security"
    "-lobjc"
  )
endif()

This is the standard CMake idiom for linking Apple frameworks. The block is gated on APPLE so it has no effect on Linux or Windows builds.

Verification

Verified on:

• macOS 15 Sequoia, Apple M3 (darwin-aarch64)
• Temurin JDK 21, libusb installed via Homebrew
• The produced libusb4java.dylib loads correctly via JNI and LibUsb.init() returns 0

The resulting darwin-aarch64 JAR has been tested with TomTomWatch connecting to a physical TomTom GPS watch over USB.