2c4b229c90 cmake: Introduce `FUZZ_LIBS` (Hennadii Stepanov)
ea929c0848 scripted-diff: Rename CMake helper module (Hennadii Stepanov)
8d238c1dfd cmake: Delete `check_cxx_source_links*` macros (Hennadii Stepanov)
71bf8294a9 cmake: Convert `check_cxx_source_compiles_with_flags` to a function (Hennadii Stepanov)
88ee6800c9 cmake: Delete `check_cxx_source_links_with_flags` macro (Hennadii Stepanov)
09e8fd25b1 build: Don't override CMake's default try_compile target (Hennadii Stepanov)
Pull request description:
This was requested in https://github.com/bitcoin/bitcoin/pull/31359#issuecomment-2515287092.
From https://github.com/bitcoin/bitcoin/pull/31359#issuecomment-2511246212:
> (Almost?) every CMake check internally uses the [`try_compile()`](https://cmake.org/cmake/help/latest/command/try_compile.html) command, whose behaviour, in turn, depends on the [`CMAKE_TRY_COMPILE_TARGET_TYPE`](https://cmake.org/cmake/help/latest/variable/CMAKE_TRY_COMPILE_TARGET_TYPE.html) variable:
>
> 1. The default value, `EXECUTABLE`, enables both compiler and linker checks.
>
> 2. The `STATIC_LIBRARY` value enables only compiler checks.
>
>
> To mimic Autotools' behaviour, we [disabled](d3f42fa08f/cmake/module/CheckSourceCompilesAndLinks.cmake (L9-L10)) linker checks by setting `CMAKE_TRY_COMPILE_TARGET_TYPE` to `STATIC_LIBRARY` globally (perhaps not the best design). This effectively separates the entire CMake script into regions where `CMAKE_TRY_COMPILE_TARGET_TYPE` is:
>
> * unset
>
> * set to `STATIC_LIBRARY`
>
> * set to `EXECUTABLE`
From https://github.com/bitcoin/bitcoin/pull/31359#issuecomment-2515287092:
> > This seems very fragile and unintuitive, and the fact that this could silently break at any point is not documented in any way. I don't think other bad design decisions should lead to us having to write even more boilerplate code to fix things that should "just work" (minus the upstream bugs).
>
> Agreed. I forgot that we set `CMAKE_TRY_COMPILE_TARGET_TYPE` globally. And even worse, it's buried in a module. If that upsets CMake internal tests, I think we should undo that.
This PR ensures that `CMAKE_TRY_COMPILE_TARGET_TYPE` is modified only within local scopes.
Additionally, the `FUZZ_LIBS` variable has been introduced to handle additional libraries required for linking, rather than link options, in certain build environment, such as OSS-Fuzz.
ACKs for top commit:
TheCharlatan:
Re-ACK 2c4b229c90
theuni:
utACK 2c4b229c90
Tree-SHA512: f72ffa8f50f216fc1a2f8027ba8ddfd4acd42b94ff6c1cb2138f2da51eb8f945660e97d3c247d7f3f7ec8dfebbccec3ab84347d6ae2e3f8a40f3d7aa8b14cde9
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