Alright, so I've decided to go the buildtools route because I think the version of MingW64 that I am using is obsolete now? I've managed to compile both MESS and MAME, but one, I can't make clean, I get this error:

Cleaning...
process_begin: CreateProcess(NULL, rm -rf build, ...) failed.
make (e=2): The system cannot find the file specified.
makefile:532: recipe for target 'clean' failed
make: [clean] Error 2 (ignored)
Cleaning genie

My make clean batch file looks like this:

@echo off
set MINGW64=C:\buildtools\vendor\mingw64
set path=C:\buildtools\vendor\mingw64\bin;C:\buildtools\vendor\mingw64\opt\bin;C:\buildtools\vendor\qt\mingw64\Qt\bin;
make clean
pause

And two, the instructions on the MAME Dev website say to run 'update' once in a while. The only update file I can find is located in \buildtools\bin, listed as 'update.bat' and when I run it, I get this error:

Updating MAME tools
====================
C:\buildtools\bin
'git' is not recognized as an internal or external command,
operable program or batch file.
The system cannot find the path specified.

I'm not really concerned that I can't run update, but I'd like make clean to work properly as this is needed sometimes.