fix bug#64409
In libusb-compat-0.1.8/libusb/libusb-dload.h, dlopen is used to load libusb.
We need to specify an absolute path.
With this fix, teensy_loader_cli doesn't immediately fail with a missing library error.
./pre-inst-env guix shell teensy-loader-cli -- teensy_loader_cli
If you merge the patch from bug#64563 first, you can't test this patch with teensy_loader_cli.