* Initialize c++ requirements before calling check_cxx_source_compiles
* libjxl implementation rely on c11 atomics (cache_aligned.cc)
It turns out that GCC requires explicitly linking to a library `atomic`
in order to support c11/atomics. gcc spec file will not handle it
directly at least not on the following Debian archs: armel, mipsel,
powerpc and riscv64.
Introduce a new cmake module to detect usage of gcc/atomic and add
missing library to the link step.
For reference:
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104248
The module looks for brotli using pkg-config if available otherwise it will look for the library in the CMAKE_PREFIX_PATH. If found a target is created that mirrors the in source build of the library.
The brotli headers do not have versioning so a minimum version is not requested.
The module looks for lcms2 using pkg-config if available otherwise it will look for the library in the CMAKE_PREFIX_PATH. If found a target is created that mirrors the in source build of the library.
The module looks for hwy using pkg-config if available otherwise it will look for the library in the `CMAKE_PREFIX_PATH`. If found a target is created that mirrors the in source build of the library.
Alexey