A little late, but I've been attempting this very same thing - I got past this step by changing msys to msys2 - there seems to have been an update or two in the last 12 years :)
- Replace "c:\devkitPro\msys\msys_shell.bat" with "c:\devkitPro\msys2\msys2_shell.bat" and
- Replace "SET PATH= ...