[Fixed] Rust failed to run custom build command for 'libxml'

[BanjoFox]

I've been getting this really annoying error about "cannot build libxml", and apparently I'd fixed it on ONE system but not others, and I never bothered to write down the fix.

When running

cargo build -vv
I -eventually- found this:

cargo:warning=src/helper_functions.h:6:29: fatal error: libxml/xmlerror.h: No such file or directory

Which is likely because I did not not have the libxml2-dev package installed.

Install it with the usual apt install libxml2-dev way and you should be good to go.