Add build instructions

[mrhappyasthma]

I'm trying to get this makefile running on Windows, and I'm having issues. I think I have most of the dependencies set up now, but it would be helpful if the README included build instructions.

[ITotalJustice]

Make sure you have the following installed:

switch-curl switch-freetype switch-sdl2 switch-sdl2_gfx switch-sdl2_image switch-sdl2_ttf switch-zlib

[ITotalJustice]

If it still fails, please post the post the build log. (Also report back if it works so that i know what to add to the build instructions!).

[mrhappyasthma]

Could you clarify how to install those?

I installed the devkitPro for Windows. And I manually installed SDL2, SDL2_Image and SDL2_ttf for windows.

Using cygwin64 I am linking against curl and zlib.

The error I'm seeing is:

aarch64-none-elf-g++.exe: error: unrecognized command line option '-mwindows'

[mrhappyasthma]

I'm able to install those specific packages on Mac. Still not sure how to install them on Windows.

[mrhappyasthma]

Okay, turns out the install instructions don't explain that you need to use pacman -S <lib> command line tool to install those deps on Windows.

After installing all of those deps, I'm getting this error:

linking atmosphere-updater.elf
d:/devkitpro/devkita64/bin/../lib/gcc/aarch64-none-elf/8.3.0/../../../../aarch64-none-elf/bin/ld.exe: D:/devkitPro/libnx/lib\libnx.a(switch_crt0.o): in function `bss_loop':
/home/fincs/pacman-packages/libnx/src/libnx-2.5.0/nx/source/runtime/switch_crt0.s:72: undefined reference to `main'
collect2.exe: error: ld returned 1 exit status
make[1]: *** [/opt/devkitpro/libnx/switch_rules:80: /d/GitHub/atmosphere-updater/atmosphere-updater.elf] Error 1
make: *** [Makefile:170: build] Error 2

[mrhappyasthma]

Ah, success! I needed to make clean first. Some of the build products must have been stale.

[ITotalJustice]

Sorry, I should've specified that you needed to use the dkp toolchain (which you did in the end).

I'm glad you managed to compile in the end, also thank you for reporting back. I'll add build instructions either later today or tomorrow (going to re-open this issue until then).