[aravis] add new port (+add to OpenCV 4 as optional feature)

[rursprung]

please note:

• i'm not part of the aravis maintainers (i'm just a user)
• i've tested this under Ubuntu 24.04 in WSL2 using a USB3 VISION camera through OpenCV (with the new aravis feature introduced in this PR) and it worked fine
• aravis currently builds a couple of binaries (arv-camera-test-0.8, arv-fake-gv-camera-0.8, arv-test-0.8 and arv-tool-0.8) which cannot be disabled at the moment (except with a patch to their build system), i've reported this to upstream: add meson option to build only the library AravisProject/aravis#962. i think they currently don't hurt and it's better if this gets fixed in upstream rather than having a patch here.
• back in 2019 @cenit already once attempted to package aravis here but that PR was abandoned later: [aravis] new port #8595

resolves #37072
resolves #3411

checklist:

• Changes comply with the maintainer guide.
• The name of the port matches an existing name for this component on https://repology.org/ if possible, and/or is strongly associated with that component on search engines.
• Optional dependencies are resolved in exactly one way. For example, if the component is built with CMake, all find_package calls are REQUIRED, are satisfied by vcpkg.json's declared dependencies, or disabled with CMAKE_DISABLE_FIND_PACKAGE_Xxx.
• The versioning scheme in vcpkg.json matches what upstream says.
• The license declaration in vcpkg.json matches what upstream says.
• The installed as the "copyright" file matches what upstream says.
• The source code of the component installed comes from an authoritative source.
• The generated "usage text" is accurate. See adding-usage for context.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is in the new port's versions file.
• Only one version is added to each modified port's versions file.

[dg0yt]

Enable opt-out from usb.

Suggested change

	"aravis"
	{
	"name": "aravis",
	"default-features": false
	}

[rursprung]

then it might be better to leave usb away as a default feature from aravis? i now went with that option to stay aligned with aravis (though i think they make it dependent on the availability of the library by default since they set it to auto)

[dg0yt]

This wrapper is pointless and not working correctly.
The code should be added to the consuming projects instead.

[rursprung]

without this wrapper i can't do find_package(Aravis REQUIRED) - i didn't find any documentation on how to resolve this (even vcpkg-cmake-wrapper.cmake is undocumented beyond the fact that it may exist). how else would you solve this?

[dg0yt]

Don't add a usage file here. The tool generates the desired information heristically for pkg-config.

[rursprung]

ok, i've removed it.
but then it just says:

aravis provides pkg-config modules:

  # Camera control and image acquisition library
  aravis-0.8

isn't this less helpful than having a clear example on what to do (as is e.g. the case with the usage i had provided)?

[rursprung]

@dg0yt: thanks a lot for your super fast review!

i now have one last CI failure in the android CI builds which i don't know how to solve:

../src/0.8.33-e9321ff061.clean/src/arvnetwork.c:352:6: error: call to undeclared function 'getifaddrs'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  352 |         if (getifaddrs (&ifap) <0)
      |             ^
../src/0.8.33-e9321ff061.clean/src/arvnetwork.c:390:2: error: call to undeclared function 'freeifaddrs'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  390 |         freeifaddrs (ifap);
      |         ^
2 errors generated.

based on labstreaminglayer/liblsl-Android#4 (unrelated library, just found the error description there) this is caused when using a too-old Android NDK as these methods were implemented more recently (Android NDK 24, see also the source code). is there a way to force the CI to build with a newer android SDK version for this port (though the log file does talk about android-ndk-r27c in the path)?

also, i just got this result on windows in the CI:

-- Performing post-build validation
D:\a\_work\1\s\ports\aravis\portfile.cmake: warning: The following executables were found in ${CURRENT_PACKAGES_DIR}/bin or ${CURRENT_PACKAGES_DIR}/debug/bin. Executables are not valid distribution targets. If these executables are build tools, consider using `vcpkg_copy_tools`. To suppress this message, add set(VCPKG_POLICY_ALLOW_EXES_IN_BIN enabled)
D:\p\aravis_arm64-windows: note: the executables are relative to ${CURRENT_PACKAGES_DIR} here
note: debug/bin/arv-camera-test-0.8.exe
note: debug/bin/arv-fake-gv-camera-0.8.exe
note: debug/bin/arv-test-0.8.exe
note: debug/bin/arv-tool-0.8.exe
note: bin/arv-camera-test-0.8.exe
note: bin/arv-fake-gv-camera-0.8.exe
note: bin/arv-test-0.8.exe
note: bin/arv-tool-0.8.exe

i guess i do need to add a patch for the build after all to skip generating these bins (at least until it's done in upstream)?

[dg0yt]

The Android problem is not the NDK (vcpkg CI has r27c) but the API level (vcpkg uses 21 as default).
For now, you must add the expected fail to scripts/ci.baseline.txt, with a comment similar to the existing ones.
(Changing vcpkg android defaults is #42080.)