Explicitly pass "--no-relax" on ArchSPARC64
(as ArchSPARC does) where gcc's default specs
set "-mrelax" which conflicts with "-Wl,-r".

Known architecture will also help extending
sparc NCG support 64-bit ABI.

Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Sergei Trofimovich <siarheit@google.com>