Add macOS build instructions. Still need to write about .app bundle

README-macOS.md

@@ -0,0 +1,48 @@
+# Building on macOS
+
+Required:
+- CMake to build dependencies
+- Hashlink (to build Universal: https://github.com/nullobsi/hashlink)
+- SDL2
+- libjpeg
+- libjpegturbo
+- libogg
+- libvorbis
+- libpng
+- openal-soft
+- zlib
+
+## Building dependencies for Universal
+I've found that using CMake makes building universal binaries on macOS a
+lot easier.
+
+Here's the process for dependencies that use CMake:
+```sh
+cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release -DCMAKE_OSX_ARCHITECTURES="x86_64;arm64" -DCMAKE_OSX_DEPLOYMENT_TARGET="10.15" -DBUILD_SHARED_LIBS=ON -DCMAKE_FIND_FRAMEWORK=LAST
+cmake --build build --config Release -j8
+sudo cmake --install build
+```
+This will build + install a CMake project as a Universal binary. It's
+important that every dependency in the chain be universal for this to
+work, otherwise you will get linking errors.
+
+Some notes:
+- When compiling Hashlink, you may need to disable `uv` and `ssl` as
+  these are not needed by MBHaxe
+
+Please see the other readme for Haxe libraries as you will need to use a
+custom version of Heaps and HLSDL.
+
+## Compiling MBHaxe
+Use `haxe compile-c.hxml` to generate the `native` directory. If you're
+going to build a .app bundle, use compile-macos.hxml instead.
+
+cd into the native directory, then use the following command to build:
+```sh
+# Sometimes needed because of HLSDL.
+sed -i -e 's/?sdl/sdl/g' sdl/Window.c hl/natives.h hl/functions.c sdl/Sdl.c
+
+clang -mmacosx-version-min=10.15 -arch x86_64 -arch arm64 -o marblegame -I . -L /usr/local/lib/ -std=c11 marblegame.c /usr/local/lib/{ui.hdll, openal.hdll, fmt.hdll, sdl.hdll} -lsdl2 -lhl
+```
+This assumes you built all the libraries and installed them to
+/usr/local/lib.