Fixups for FTBFS patch to build on Sparc64

@terceiro
Thanks to your previous upload at !2 (merged).

I was added some fixup to sparc64 and hurd build. Please apply once more.

• Drop hurd-amd64 and hurd-i386 from sanitizer build.
• Drop sparc64 from address-sanitizer build. Address sanitizer is only available for 32bit sparc.