devel/simavr: fix build on GCC architectures

Merge the first hunk of https://github.com/buserror/simavr/commit/c2c8e40ff219f78779fc2743f0c1ffbabe159e37#diff-d06f1c6c1d6e380263f5450d5b70ca2b.diff to fix build. The whole patch can't be merged, the other two hunks don't apply.

PR: 246719
Approved by: felix@palmen-it.de (maintainer)