package/cryptopp: Backport gcc compatibility patch

package/cryptopp: Backport gcc compatibility patch

Import patch from cryptopp upstream which fixes the gcc version checks
for using attribute deprecated with messages. Fixes build with host
gcc versions < 4.5.

Signed-off-by: Julian Scheel <julian@jusst.de>
[Thomas:
 - directly use the patch from upstream through <pkg>_PATCH rather
   than storing it in package/cryptopp/, as it helps avoiding
   line-endings problems: upstream has the source code with DOS line
   endings.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>