[minizip] Make BZip2 an optional feature

[rknall]

If the BZip2 package has not been found, ensure that the library does
not assume it is. This would stop any build on targets where bzip2 is
not installed. This can either be the bzip2 package provided by vcpkg
or locally on the system.

Feature:

• Allow optionally to enable bzip2 supprt

[rknall]

I apologize for resubmitting this patch. Had some fun with the git rebase

[cenit]

This can produce inconsistencies. What if you install bzip2 on your own and then minizip? Minizip would catch bzip2 and enable the feature without your knowledge (and vcpkg’s). Then you could remove easily bzip2, leaving a broken minizip behind you.
This feature requires a different approach imho

[Rastaban]

The feature names are scoped different from the package names, so in cases like this the feature is typically given a name like bzip2 instead of bzip2support.

Making bzip2 a default feature would avoid breaking current users. I haven't used minzip so I don't know what most project would expect.

[Rastaban]

Thank you for the PR! You are off to a good start. Rather than making the find_package optional, add a new CMake option that can be passed in from the vcpkg_configure_cmake call in the portfile and is only set to off when the bzip feature is not used. That will make the behavior in the CI system more robust (we sometimes install everything and don't guarantee an order for ports without dependencies, so bzip2 may or may not be installed before). That should also resolve @cenit's concern. I can find you an example of another port that does that if it would be helpful, just let me know.

Also bump the version in the control file to 1.2.11-5, it helps with the vcpkg update command.

[rknall]

Thank you for the comments. Just as a background, we have included minizip in our Wireshark distribution (as of yesterday), but would prefer going the vcpkg route instead of building it ourselves. I do share the concerns of making a now required feature optional, and already also found a few corners where this breaks compatibility. I will try to make the required changes as stated by cenit and resubmit

[rknall]

To ensure backwards compatibility, I have added the bzip2 feature to both libkml and collada-dom. Not sure if they need it though, but this way they will be built as before.

[Rastaban]

You can make an optional feature on by default by adding Default-Features: bzip2 to the CONTROL file. It would gives this behavior on install:

has default bzip2 feature
vcpkg install minzip

disables bzip2 feature and only installs the core
vcpkg install minzip[core]

I am willing to let it be an op-in feature for now, but if it causes issues then it will be turned into a default-feature in the future.