Mame 139 not compiling

[Yoast]

I've recently been trying to compile Mame139 from source as I wanted to patch it to remove the nag screen. I downloaded the source from here.
But whenever I compile I keep getting errors. The first error I got was a Werror=unused-set-variable warning. I disabled Werror in the makefile, but continued to get errors. The code hasn't been modified by me so is there something wrong with the source code or am I doing something wrong?

I tried compiling without patching and got the same errors, and even tried patching other versions (138 and 140), but they would not compile either.

[Yoast]

I have tried on both windows and linux, by the way.

[dankcushions]

@yoast we don't run any standard mame cores. compiling them takes some effort, and they won't be supported by retropie directly.

you can see how to compile here: https://choccyhobnob.com/raspberry-pi/compiling-mame-on-raspberry-pi/ (although, these guidelines are for raspbian stretch which retropie also doesn't use).

all that said, there's already an option in lr-mame2010 to remove the nag screen... so, just use that? https://github.com/libretro/mame2010-libretro/blob/5c516c7e33b5637087eec034db5cfe7a25681340/src/osd/retro/retromapper.c#L52

[jonnykesh]

I honestly don't see what this has to do with RetroPie.
Lr-mame2010 is a pre-compiled binary in RetroPie and is available to be installed from the setup script. And I'm almost 100% sure that the libretro cores have an option to disable the nag screen and warning screen within the RetroArch menu.