Add way to compile gz-msgs10 via cross-compilation

[traversaro]

Desired behavior

I will like (and probably will work on) a way to compile gz-msgs10 via cross-compilation. The way described in

gz-msgs/CMakeLists.txt

Line 27 in 0472ba0

# Cross-compilation related options

is now outdated and not working anymore after the changes in #368 .

Alternatives considered

Never cross-compile gz-msgs10 again (not feasible at the moment for osx-arm64 builds on conda-forge, where there are no osx-arm64 built machines).

Implementation suggestion

Not sure, I need to look into that.

Additional context

See conda-forge/gz-msgs-feedstock#16 (comment) .

[traversaro]

I will probably work on this as part of conda-forge/gz-msgs-feedstock#16 (at the minimum in form of conda-specific patches), but I wanted to have an issue for this to aid any users that could be interested in this.

[azeey]

Fixed by #392.