Generally, the hard part isn't the cross compiler (nor, these days, the cross binutils), but the cross libraries. There are at least 3 ways (/usr/lib/$ARCH, /usr/$ARCH/lib, /$CHROOT/usr/lib/) to set up the libraries, all incompatible with each other.

Zig is notable for putting a lot of work into hard-coding basic C libraries, though of course you still need a scattering of other C libraries for most real-world programs.

(for a sufficiently advanced language ecosystem, the language's own libraries should be easy enough)