make_src_dist.py: Vendor simpleini SDL_audiolib

Explicitly set `-DDEVILUTIONX_SYSTEM_SDL_AUDIOLIB=OFF`
and `-DDEVILUTIONX_SYSTEM_SIMPLEINI=OFF` because we now
also support the system versions of these.

tools/make_src_dist.py

@@ -37,6 +37,7 @@ import sys
 # 2. Require devilutionx forks (all others).
 _DEPS = ['asio', 'libmpq', 'libsmackerdec',
          'libzt', 'sdl_audiolib', 'simpleini']
+_ALWAYS_VENDORED_DEPS = ['asio', 'libmpq', 'libsmackerdec', 'libzt']
 
 # These dependencies are not vendored by default.
 # Run with `--fully_vendored` to include them.
@@ -82,6 +83,8 @@ def main():
 
 	configure_args = [f'-S{_ROOT_DIR}',
                    f'-B{_BUILD_DIR}', '-DBUILD_ASSETS_MPQ=ON']
+	for dep in sorted(set(_DEPS) - set(_ALWAYS_VENDORED_DEPS)):
+		configure_args.append(f'-DDEVILUTIONX_SYSTEM_{dep.upper()}=OFF')
 	if args.fully_vendored:
 		for dep in _DEPS_NOT_VENDORED_BY_DEFAULT:
 			configure_args.append(f'-DDEVILUTIONX_SYSTEM_{dep.upper()}=OFF')