CMAKE_COMPILER_IS_GNUCC is obsolete variable and can be replaced with
CMAKE_C_COMPILER_ID (also available since early CMake versions).
In the past CMake versions also LCC and QCC compilers had this varible
set to boolean true but these aren't relevant here.
This PR adds support to the cmake build scripts so to allow building SDL with the Tiny C Compiler (tcc).
TinyCC supports the subset of C99 used by SDL and will complete the build once the --version-script linker flag is removed. The changes have been tested with various build configurations, including X11 and Wayland, and using tcc version 0.9.28rc 2025-10-27 mob@f4e01bfc on x86_64 Linux.
main features:
- No more sdl-build-options/sdl-shared-build-options/sdl-global-options
- Dependency information is stored on SDL3-collector for sdl3.pc
- Use helper functions to modify the SDL targets;
- sdl_sources to add sources
- sdl_glob_sources to add glob soruces
- sdl_link_dependency to add a link dependency that might also
appear in sdl3.pc/SDL3Config.cmake
- sdl_compile_definitions to add macro's
- sdl_compile_options for compile options
- sdl_include_directories for include directories
They avoid repeated checks for existence of the SDL targets
- A nice feature of the previous is the ability to generate
a sdl3.pc or SDL3Config.cmake that describes its dependencies
accurately.
various:
- remove duplicate libc symbol list
- add CheckVulkan
- remove unused HAVE_MPROTECT
- add checks for getpagesize
