add (commented out) debian hardening option to debian/rules
check for GMP and don't build GMP runtime if it doesn't exist
Merge branch 'master' into pvs/devel
Merge branch 'pvs/include-restructure' into pvs/devel
allow libgmp-dev as an option next to libgmp3-dev
install the more generic name libgmp-dev in the CI env
add new package version

[skip ci]