6271cb42b2
Add seven platform bridge implementations and the shared native target header: el_native_target.h, el_appkit.m, el_uikit.m, el_android.c, el_gtk4.c, el_sdl2.c, el_lvgl.c, el_win32.c, el_runtime_win32.c. Each bridge implements the 33 __widget_* C builtins declared in el_native_target.h for its platform toolkit. el_runtime_win32.c provides a POSIX-free runtime stub for cross-compiled Win32 targets.