Cherry-picked patches for ncurses

Written terribly early in the morning in English • Tags: ,

In order to reduce the number of vulnerabilities on my systems, I added some patches to devel/ncurses (and devel/ncursesw) to address CVE-2018-19211, CVE-2019-17594, and CVE-2019-17595. Version 6.1nb7 includes the patches.