use x86_64-w64-mingw32- prefix for tools like dlltool as necessary
use x86_64-w64-mingw32- prefix for tools like dlltool as necessary

This fixes architecture mismatches when cross-compiling.

lwahlmeier/avian,dicej/avian,minor-jason/avian,minor-jason/avian,ucdseniordesign/avian,dicej/avian,MaartenR/avian,MaartenR/avian,joshuawarner32/avian,joshuawarner32/avian,bigfatbrowncat/avian-pack.avian,lwahlmeier/avian,marcinolawski/avian,dicej/avian,bgould/avian,ucdseniordesign/avian,bigfatbrowncat/avian-pack.avian,lostdj/avian,MaartenR/avian,marcinolawski/avian,lostdj/avian,marcinolawski/avian,lostdj/avian,bgould/avian,minor-jason/avian,bigfatbrowncat/avian-pack.avian,joshuawarner32/avian,bgould/avian,joshuawarner32/avian,ucdseniordesign/avian,lwahlmeier/avian,minor-jason/avian,MaartenR/avian,dicej/avian,bigfatbrowncat/avian-pack.avian,ucdseniordesign/avian,marcinolawski/avian,lwahlmeier/avian,bgould/avian,lostdj/avian