When compiling XS modules on OSX, you might get some warnings like:
ld: warning: object file (SystemDirectory.o) was built for
newer OSX version (10.11) than being linked (10.4)
This can be eliminated by specifying your OSX version, when building new perls under Perlbrew
PERLBREW_CONFIGURE_FLAGS='-de -Dccflags="-mmacosx-version-min=10.12" \
-Dccdlflags="-mmacosx-version-min=10.12" \
-Dldflags="-mmacosx-version-min=10.12" \
-Dlddlflags="-mmacosx-version-min=10.12"' \
perlbrew install 5.22.3 --64all -j 2