This is a summary of points for discussion about improving the CMake build system.

• Do actually export config.
  The current config is written like a find module (legacy: inspecting the system), instead of using build-time information (modern: export from the build).
• Do not build static and shared libs in the same time.
  This looks familiar for users of autotools, but it comes with a price: It adds complexity, including additional user-facing variables. Users must select the matching target name even if they just build a single config. It requires a different name for MSVC import libs, currently breaking the unmodified pc files. ...
• Add aliases of the exported targets, for embedding the PCRE2 build via add_directory.
• Document the canonical CMake config usage.
• Add a post-install usage test to CI.
• Follow widely used CMake style.
  lower_case(commands). Don't repeat condition in else() and endif(). Less whitespace.

References to previous discussion:

• Add target_include_directories to CMakefile #113
• 2410fbe#commitcomment-68176307
• https://lists.exim.org/lurker/message/20210701.070030.8dbb0b5b.en.html

Who uses the CMake build system?

• vcpkg. Apart from avoiding slow autotools builds on Windows, the default configurations build for release and debug, for the benefit of Visual Studio users.
• (I can add more here base on comments.)