* debian/patches/unix-pthread-trac-4523: Apply patch from upstream BTS #4523 to add missing linker reference to pthread, which caused linking failuers in depending packages when attempting to link with the unix library on armel. * debian/rules, debian/patches/ghc-pkg-pthread: Add -optl-pthread to explicitly link with -lpthread. This is a temporary fix to make the GHC used for bootstrapping work correctly on armel.