FindLibudev: Link hidapi and libusb with libudev in static builds on Linux

[fwcd]

Follow-up to the other static linking PRs (#12291, #12292), some of the hidapi-related dependencies have a dependency on libudev that we'll have to link in explicitly in static builds (see e.g. this build):

Click to see full linker error

/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libhidapi-hidraw.a(hid.c.o): in function `create_device_info_for_device':
hid.c:(.text+0x449): undefined reference to `udev_device_get_syspath'
/usr/bin/ld: hid.c:(.text+0x456): undefined reference to `udev_device_get_devnode'
/usr/bin/ld: hid.c:(.text+0x46c): undefined reference to `udev_device_get_parent_with_subsystem_devtype'
/usr/bin/ld: hid.c:(.text+0x48e): undefined reference to `udev_device_get_sysattr_value'
/usr/bin/ld: hid.c:(.text+0x9bf): undefined reference to `udev_device_get_parent_with_subsystem_devtype'
/usr/bin/ld: hid.c:(.text+0x9da): undefined reference to `udev_device_get_sysattr_value'
/usr/bin/ld: hid.c:(.text+0x9f5): undefined reference to `udev_device_get_sysattr_value'
/usr/bin/ld: hid.c:(.text+0xa18): undefined reference to `udev_device_get_sysattr_value'
/usr/bin/ld: hid.c:(.text+0xa47): undefined reference to `udev_device_get_parent_with_subsystem_devtype'
/usr/bin/ld: hid.c:(.text+0xa5f): undefined reference to `udev_device_get_sysattr_value'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libhidapi-hidraw.a(hid.c.o): in function `hid_enumerate':
hid.c:(.text+0xeb6): undefined reference to `udev_new'
/usr/bin/ld: hid.c:(.text+0xecc): undefined reference to `udev_enumerate_new'
/usr/bin/ld: hid.c:(.text+0xee3): undefined reference to `udev_enumerate_add_match_subsystem'
/usr/bin/ld: hid.c:(.text+0xeeb): undefined reference to `udev_enumerate_scan_devices'
/usr/bin/ld: hid.c:(.text+0xef3): undefined reference to `udev_enumerate_get_list_entry'
/usr/bin/ld: hid.c:(.text+0xf3a): undefined reference to `udev_list_entry_get_name'
/usr/bin/ld: hid.c:(.text+0xfe7): undefined reference to `udev_device_new_from_syspath'
/usr/bin/ld: hid.c:(.text+0x1004): undefined reference to `udev_device_unref'
/usr/bin/ld: hid.c:(.text+0x100c): undefined reference to `udev_list_entry_get_next'
/usr/bin/ld: hid.c:(.text+0x1022): undefined reference to `udev_enumerate_unref'
/usr/bin/ld: hid.c:(.text+0x102a): undefined reference to `udev_unref'
/usr/bin/ld: hid.c:(.text+0x10bd): undefined reference to `udev_enumerate_unref'
/usr/bin/ld: hid.c:(.text+0x10c5): undefined reference to `udev_unref'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libhidapi-hidraw.a(hid.c.o): in function `hid_get_device_info':
hid.c:(.text+0x183c): undefined reference to `udev_new'
/usr/bin/ld: hid.c:(.text+0x185a): undefined reference to `udev_device_new_from_devnum'
/usr/bin/ld: hid.c:(.text+0x187a): undefined reference to `udev_device_unref'
/usr/bin/ld: hid.c:(.text+0x1882): undefined reference to `udev_unref'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libusb-1.0.a(linux_udev.o): in function `udev_hotplug_event':
linux_udev.c:(.text+0x2c): undefined reference to `udev_device_get_action'
/usr/bin/ld: linux_udev.c:(.text+0x5c): undefined reference to `udev_device_get_devnode'
/usr/bin/ld: linux_udev.c:(.text+0x6c): undefined reference to `udev_device_get_sysname'
/usr/bin/ld: linux_udev.c:(.text+0xa2): undefined reference to `udev_device_unref'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libusb-1.0.a(linux_udev.o): in function `linux_udev_event_thread_main':
linux_udev.c:(.text+0x247): undefined reference to `udev_monitor_receive_device'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libusb-1.0.a(linux_udev.o): in function `linux_udev_start_event_monitor':
linux_udev.c:(.text+0x2f6): undefined reference to `udev_new'
/usr/bin/ld: linux_udev.c:(.text+0x315): undefined reference to `udev_monitor_new_from_netlink'
/usr/bin/ld: linux_udev.c:(.text+0x33b): undefined reference to `udev_monitor_filter_add_match_subsystem_devtype'
/usr/bin/ld: linux_udev.c:(.text+0x34f): undefined reference to `udev_monitor_enable_receiving'
/usr/bin/ld: linux_udev.c:(.text+0x363): undefined reference to `udev_monitor_get_fd'
/usr/bin/ld: linux_udev.c:(.text+0x480): undefined reference to `udev_monitor_unref'
/usr/bin/ld: linux_udev.c:(.text+0x4a1): undefined reference to `udev_unref'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libusb-1.0.a(linux_udev.o): in function `linux_udev_stop_event_monitor':
linux_udev.c:(.text+0x5b0): undefined reference to `udev_monitor_unref'
/usr/bin/ld: linux_udev.c:(.text+0x5d1): undefined reference to `udev_unref'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libusb-1.0.a(linux_udev.o): in function `linux_udev_scan_devices':
linux_udev.c:(.text+0x63d): undefined reference to `udev_enumerate_new'
/usr/bin/ld: linux_udev.c:(.text+0x65d): undefined reference to `udev_enumerate_add_match_subsystem'
/usr/bin/ld: linux_udev.c:(.text+0x673): undefined reference to `udev_enumerate_add_match_property'
/usr/bin/ld: linux_udev.c:(.text+0x67b): undefined reference to `udev_enumerate_scan_devices'
/usr/bin/ld: linux_udev.c:(.text+0x683): undefined reference to `udev_enumerate_get_list_entry'
/usr/bin/ld: linux_udev.c:(.text+0x6a4): undefined reference to `udev_list_entry_get_name'
/usr/bin/ld: linux_udev.c:(.text+0x6bd): undefined reference to `udev_device_new_from_syspath'
/usr/bin/ld: linux_udev.c:(.text+0x6c8): undefined reference to `udev_device_get_devnode'
/usr/bin/ld: linux_udev.c:(.text+0x6d8): undefined reference to `udev_device_get_sysname'
/usr/bin/ld: linux_udev.c:(.text+0x721): undefined reference to `udev_device_unref'
/usr/bin/ld: linux_udev.c:(.text+0x729): undefined reference to `udev_list_entry_get_next'
/usr/bin/ld: linux_udev.c:(.text+0x73f): undefined reference to `udev_enumerate_unref'
/usr/bin/ld: /home/runner/work/m1xxx/m1xxx/vcpkg/installed/x64-linux/lib/libusb-1.0.a(linux_udev.o): in function `linux_udev_hotplug_poll':
linux_udev.c:(.text+0x7c8): undefined reference to `udev_monitor_receive_device'

Note that libudev itself will likely still have to be linked dynamically, since it is part of the systemd libraries.

[fwcd]

Hm, maybe we should add a new Findudev module, since we may also have to link this in LibUSB...

[fwcd]

I've named the module Libudev since both the pkgconfig and the header are named libudev (rather than just udev) and added a missing find_path. This seems to work, no more udev errors, therefore I'll mark this as ready for review!

[daschuer]

LGTM