build: Drop unneeded macOS framework dependencies #20496

Bitcoin Core codebase does not contain direct dependencies on the ApplicationServices and IOKit frameworks.

utACK ec4a46dd9c158e1a0de144e9abb260da941aa702

cr ACK ec4a46dd9c158e1a0de144e9abb260da941aa702: patch looks correct!

Thanks for removing unused old cruft!

Tested ACK ec4a46dd9c158e1a0de144e9abb260da941aa702 (not depends build).

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Conflicts

No conflicts as of last run.

In future it would be good if PRs like this had slightly more informative PR descriptions and commit messages.

Bitcoin Core codebase does not contain direct dependencies on the ApplicationServices and IOKit frameworks.

Our C++ code might not contain direct dependencies on these frameworks, but that's not really the point of these checks. We need to test linking against some frameworks, and adding them to QT_LIBS if successful, so that when we try and link against -lqcocoa, it will work. i.e in #19716 I've actually added additional framework checks (while removing IOKit), as without them, the -qcocoa static plugin check would fail.

For example, if with that branch, you drop off the link check for -framework Carbon, when you configure you'll see:

checking for static Qt plugins: -lqminimal... yes
checking whether the linker accepts -framework QuartzCore... yes
checking whether the linker accepts -framework IOSurface... yes
checking for static Qt plugins: -lqcocoa... no
configure: WARNING: Could not resolve: -lqcocoa; bitcoin-qt frontend will not be built

# config.log
Undefined symbols for architecture x86_64:
  "_kTISPropertyInputSourceLanguages", referenced from:
      QCocoaInputContext::updateLocale() in libqcocoa.a(qcocoainputcontext.o)
  "_TISCopyInputMethodKeyboardLayoutOverride", referenced from:
      QCocoaKeyMapper::updateKeyboard() in libqcocoa.a(qcocoakeymapper.o)
  "_GetCurrentKeyModifiers", referenced from:
      QCocoaKeyMapper::queryKeyboardModifiers() in libqcocoa.a(qcocoakeymapper.o)

as the linker can't resolve the symbols from the Carbon framework. This means that we won't build bitcoin-qt.

Also, the commit messages say "uneeded X framework dependency". However the macOS bitcoin-qt binaries we release do have a dependency on the IOKit and ApplicationServices frameworks (among many others).

I do agree that some of these checks are a bit arbitrary and there is opportunity to better document this behaviour.