cmake: fix build with Qt 6.10

[Chiitoo]

The 'Qt6FooPrivate' targets have been split into separate CMake files in Qt 6.9, and require a 'find_package(Qt6FooPrivate)' call starting with Qt 6.10.

See also: https://bugreports.qt.io/browse/QTBUG-87776

[Chiitoo]

I've been indecisive with regards to style in that, where to put the if block, since on one hand it might look prettier below them all, but on the other hand, I like them to be close to the other Qt package calls.

For some, like this and screengrab, I noticed that the if call doesn't quite work always if before some of the other calls (sorted alphabetically), I guess because the Qt Gui target (or Core even) has not been found yet, so putting it below them all like here works without additional shenanigans... so maybe that makes most sense?

[tsujan]

Strange! pcmanfm-qt doesn't depend on any private header and so, this shouldn't be needed.

[tsujan]

@Chiitoo
Could you please be more specific in this case and paste the error message you got?

[Chiitoo]

Yeah, this comes from fm-qt6, so I was a bit uncertain how to go about it here:

CMake Error at /usr/share/cmake/fm-qt6/fm-qt6-targets.cmake:61 (set_target_properties):
  The link interface of target "fm-qt6" contains:

    Qt6::GuiPrivate

  but the target was not found.  Possible reasons include:

    * There is a typo in the target name.
    * A find_package call is missing for an IMPORTED target.
    * An ALIAS target is missing.

Call Stack (most recent call first):
  /usr/share/cmake/fm-qt6/fm-qt6-config.cmake:64 (include)
  CMakeLists.txt:32 (find_package)

[tsujan]

Does this error happen after you apply lxqt/libfm-qt#1060 and compile and install libfm-qt with it?

[Chiitoo]

Uhm, looking at my build logs, it seems that I might have not merged the patched libfm-qt build the other day... only compiled it... so yeah, this seems unnecessary after all.

Thanks for noticing something is off!

[tsujan]

Thank you for taking care of this! Your PRs can be used before they're merged wherever Qt 6.10 appears.