aclocal.m4: add OSHurd (debian patch)
ghc treats OSUnknown (and GNU/Hurd) as non-ELF target.
This causes panic in native codegenerator when trying
to build PIC code:
... -- all other platforms howToAccessLabel dflags _ _ _ _ _ | not (positionIndependent dflags) = AccessDirectly | otherwise = panic "howToAccessLabel: PIC not defined for this platform"
This change declares new 'OSHurd' and marks it as an
ELF target. Fixes building ghc-stage2 on i686-unknown-gnu0.9.
Patch provided by "Pino" via Samuel Thibault and taken from
Signed-off-by: Sergei Trofimovich <email@example.com>