Various scripts for cross-compiling for x64 MinGW

src/build-* files contain bash script functions for the following purposes:

• src/build-host contains scripts for building required host software

• src/build-xc contains scripts for building a cross-compiler

• src/build-target contains scripts for building target stuff

Some built_target_* stuff currently requires to be built on WSL2, because of it executing windows binaries or otherwise interacting with the target system.

Build order is a TODO

List of prerequisites is a TODO

src/download-sources is a script which downloads all the required software and patches it

src/env-* files contain environment variables which define target directories, CFLAGS, etc.

misc directory contain pkg-config files, custom Makefiles, configuration files and other things.

First of all, /mingw directory (or symlink to a directory) of the following structure should exist:

(/x -> /y means 'x' must be a symlink to the directory named 'y')

/mingw/
/mingw/lib/
/mingw/lib64 -> /mingw/lib
/mingw/x86_64-w64-mingw32/
/mingw/mingw -> /mingw/x86_64-w64-mingw32

Yes, I know that /mingw/mingw sounds weird, but that's it. GCC requires it.

Maybe this could be fixed. I'll need to take a deeper look at GCC configuration options.

In case of WSL2, /mingw should be a symlink to C:\MinGW.

New-Item -ItemType  Directory -Path 'C:\' -Name 'MinGW'
Set-Location 'C:\MinGW'
New-Item -ItemType Directory -Name 'lib'
New-Item -ItemType Junction -Name 'lib64' -Target '.\lib'
New-Item -ItemType Directory -Name 'x86_64-w64-mingw32'
New-Item -ItemType Junction -Name 'mingw' -Target '.\x86_64-w64-mingw32'

(then inside WSL2)

sudo ln -sf /mnt/c/MinGW /mingw