libssh: fix some -Werror=strict-overflow build failures
Add fixes for some of the build failures caused by strict-overflow
warnings. Patches #1, #2, and #4 are upstream. Patch #3 is pending
upstream.
Fixes:
http://autobuild.buildroot.net/results/923/
9239f230629ca4e381af5e8f43989997d9bfde99/
http://autobuild.buildroot.net/results/618/
6187b92bcdfd9281683c37906ae74f2e0c5e6d0e/
http://autobuild.buildroot.net/results/9eb/
9eb5ed92a923f0c038e3d913289eddc1cda1b62f/
Cc: Scott Fan <fancp2007@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>