Allow the Visual Studio project to define HAVE_LIBC=0 to enable building without a C runtime on Windows entirely through Visual Studio project changes.
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
I ran this script in the include directory:
```sh
sed -i '' -e 's,#include "\(SDL.*\)",#include <SDL3/\1>,' *.h
```
I ran this script in the src directory:
```sh
for i in ../include/SDL3/SDL*.h
do hdr=$(basename $i)
if [ x"$(echo $hdr | egrep 'SDL_main|SDL_name|SDL_test|SDL_syswm|SDL_opengl|SDL_egl|SDL_vulkan')" != x ]; then
find . -type f -exec sed -i '' -e 's,#include "\('$hdr'\)",#include <SDL3/\1>,' {} \;
else
find . -type f -exec sed -i '' -e '/#include "'$hdr'"/d' {} \;
fi
done
```
Fixes https://github.com/libsdl-org/SDL/issues/6575