libspl tries to detect sparc64 by checking whether __sparc64__
is defined. Unfortunately, this assumption is not correct as
sparc64 does not define __sparc64__ but it defines __sparc__
and __arch64__ instead. This leads to sparc64 being detected
as 32-Bit sparc and the build fails because both _ILP32 and
_LP64 are defined in this case.
To fix the problem, remove the checks for __sparc64__ and
just check __arch64__ if a sparc host was previously
detected with __sparc__.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Closes#5913