AutoMoc generates because moc settings changed, not uic.
Remove the output file before invoking moc in case the case of source file has changed on disk. Recent versions of clang warn when the case of the include directive (which does change) doesn't match the case of the file on disk.
We've made several attempts to add a dummy symbol to `mocs_compilation.cpp`
when there are no automoc sources:
* commit 4a9daae483 (automoc: silence linker warning on macos,
2022-05-25, v3.24.0-rc1~55^2)
* commit 844244ccdc (automoc: avoid compiler warnings in linker-warning-
silencing code, 2022-08-10, v3.24.1~6^2)
* commit fc8628389f (automoc: avoid more compiler warnings in linker-
warning-silencing code, 2022-08-29)
The last attempt derives a symbol name from the path to the source
file, but that breaks reproducible builds because it is not stable
w.r.t. the location of the build tree. Revert all these attempts
for the 3.24 release series, and return to what 3.23 and below did.
Further investigation will be needed to resolve the original issue.
Fixes: #23937
Issue: #23551, #23823, #23823
Revise the approach from commit 844244ccdc (automoc: avoid compiler warnings in linker-warning-silencing code, 2022-08-10, v3.24.1~6^2) to avoid `-Wmissing-declarations` warnings too. Issue: #23823
Revise the code added by !7296 (merged). Make cmake_automoc_silence_linker_warning less warning-y. Fix weak-tables clang warning and copyable-polymorph clazy warning. Fixes: #23823
Extend the change from commit 5ad8862318 (Source: Convince NVHPC that RAII variables are used, 2021-04-26, v3.21.0-rc1~254^2~1) to apply to LCC too.
when an empty `mocs_compilation.cpp` is included in a static library, the macos linker emits a warning: ``` /Applications/Xcode13.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: path/To/Library.a(mocs_compilation.cpp.o) has no symbols ``` we therefore generate a globally visible weak symbol in the form of a virtual function table
When merging a new set of uic options with a base set of options, such as when a source file has a non-empty AUTOUIC_OPTIONS property, the test for whether to support options starting with two hyphens was only testing if the Qt major version was exactly 5 rather than at least 5. That had the effect of preventing such options from being merged correctly when using Qt6, so new and base options would both be present instead of the single merged option from the source file properties. Update the version check and rename function arguments to avoid misrepresenting what they mean. Note that uic accepts long option names with a single hyphen too. See Qt docs for QCommandLineParser::ParseAsLongOptions for confirmation.