[usbipdcpp] New port: A C++ library for creating usbip servers

[yunsmall]

Summary

This PR adds a new port for usbipdcpp, a C++ library for creating USB/IP servers.

Features

• USB/IP server implementation via libusb (works on all libusb-compatible platforms)
• Virtual HID device support (cross-platform, no libusb required)
• Hot-plug support for automatic device insertion/removal detection
• Asynchronous architecture using C++20 coroutines and asio
• Extensible design with abstract interfaces

Features available

• coroutine: Use C++20 coroutine-based implementation
• libusb: Build libusb-based server components for physical USB device forwarding

Usage

find_package(usbipdcpp CONFIG REQUIRED)
target_link_libraries(main PRIVATE usbipdcpp::usbipdcpp)

# With libusb support
find_package(usbipdcpp CONFIG REQUIRED COMPONENTS libusb)
target_link_libraries(main PRIVATE usbipdcpp::usbipdcpp usbipdcpp::libusb)

Checklist

- Changes comply with the https://github.com/microsoft/vcpkg-docs/blob/main/vcpkg/contributing/maintainer-guide.md.
- The packaged project shows strong association with the chosen port name.
  - The port name follows the 'GitHubOrg-GitHubRepo' form or equivalent Owner-Project form (github.com/yunsmall/usbipdcpp).
- Optional dependencies of the build are all controlled by the port (libusb is controlled by libusb feature).
- The versioning scheme in vcpkg.json matches what upstream says.
- The license declaration in vcpkg.json matches what upstream says (Apache 2.0).
- The installed as the "copyright" file matches what upstream says.
- The source code of the component installed comes from an authoritative source (GitHub release).
- The generated "usage text" is brief and accurate.
- The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
- Exactly one version is added in each modified versions file.

[yunsmall]

@microsoft-github-policy-service agree

[vicroms]

Is this an alternative (see our docs)?

[yunsmall]

@vicroms Thank you for the review! I've made the following changes:

1. ✅ Used vcpkg_check_features instead of manual if/else
2. ✅ Removed unnecessary environment variable operations
3. ✅ Simplified vcpkg_cmake_config_fixup
4. ✅ Simplified the usage file

Regarding whether coroutine is an alternative: It's not a mutually exclusive alternative but an internal implementation detail (similar to bullet3's double/single precision feature), which is transparent to users.

Also added a busywait feature for lower latency mode.

[dg0yt]

FTR there is PR template for new ports, with a checklist.

[dg0yt]

Quote for CMake language.

Suggested change

	-DPKG_CONFIG_EXECUTABLE="${PKGCONFIG}"
	"-DPKG_CONFIG_EXECUTABLE=${PKGCONFIG}"

[dg0yt]

Align with heuristical output from vcpkg's tool.

Suggested change

	The package usbipdcpp provides CMake targets:
	find_package(usbipdcpp CONFIG REQUIRED)
	target_link_libraries(main PRIVATE usbipdcpp::usbipdcpp usbipdcpp::libusb)
	usbipdcpp provides CMake targets:
	find_package(usbipdcpp CONFIG REQUIRED)
	target_link_libraries(main PRIVATE usbipdcpp::usbipdcpp usbipdcpp::libusb)

Do users really need to add/use two targets?

libusb seems to be optional. Is usbipdcpp::libusb an actual artifact or just representing the external libusb?

[yunsmall]

usbipdcpp::libusb is an actual artifact (a static library usbipdcpp_libusb), not just a wrapper for external libusb. It contains the libusb-based server implementation code.

The structure is:

• usbipdcpp::usbipdcpp - base library (always built)
• usbipdcpp::libusb - optional component with libusb server implementation (only built when libusb feature is enabled)

Users need to link both targets when using the libusb feature because usbipdcpp::libusb depends on usbipdcpp::usbipdcpp and provides additional functionality for physical USB device forwarding.

[yunsmall]

@dg0yt Thank you for the review! I've applied all the suggested changes:

1. ✅ Updated to REF "v${VERSION}"
2. ✅ Fixed FEATURES indentation
3. ✅ Added quotes for CMake options
4. ✅ Updated usage file format

Regarding the two targets: usbipdcpp::libusb is an actual artifact (a static library usbipdcpp_libusb), not just a wrapper for
external libusb. It contains the libusb-based server implementation code. Users need to link both targets when using the libusb feature.