Prefix changed in debian, include "gnu" in the commandline.
Signed-off-by: NCarlos O'Donell <carlos@parisc-linux.org>

Ensure the compiler version is new enough (>= 3.3)
Signed-off-by: NRandolph Chung <tausq@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>