Use native x86_64 instructions on x32
This patch enables a few native 64-bit integer instructions
on x32 which are available on this architecture despite using
32-bit pointers. These instructions are present on x86_64 but
not on x86 and ghc checks the size of (void *) to determine
that. This method fails on x32 since despite using 32-bit
pointers and hence sizeof(void *) == 4, it still uses the
full x86_64 instruction set and software-emulated variants
of the aforementioned 64-bit integer instructions are
therefore not present in the toolchain which will make ghc
fail to build on x32.
See: https://ghc.haskell.org/trac/ghc/ticket/11571
Gbp-Pq: Name x32-use-native-x86_64-insn.patch