gdb: use the PKGVERSION and BUGURL options

This patch makes gdb benefit from the TOOLCHAIN_PKGVERSION and
TOOLCHAIN_BUGURL options.

Signed-off-by: "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>

 reporter_name="Harold Grovesteen"

 reporter_url="http://sourceware.org/ml/crossgcc/2009-11/msg00052.html"

 reporter_comment=""