My impression is that both perl and XS module should be compiled with the same compiler (useful discussion here: How to make an XS module with a different C compiler?). Ot at least it removes an uncertainty with your troubleshooting.

To see what compiler my perl is compiled with I do: perl -MConfig -e 'print $Config{cc}' (likewise print the Config hash to see cppflags and ldflags).

bw, bliako