debug/gdb: simplify the dependency logic

Signed-off-by: Cody P Schafer <dev@codyps.com>
Message-Id: <1d9659fcf6a9c7694ad2.1399687691@localhost>
Patchwork-Id: 347583

 reporter_name="Julien DUSSER"

 reporter_url="http://sourceware.org/ml/crossgcc/2008-10/msg00054.html"

 reporter_comment="Soft-float for the 405 PowerPC"