GNUInstallDirs: Add RUNSTATEDIR variable
Matches runstatedir
from https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
Topic-rename: GNUInstallDirs-add-RUNSTATEDIR
Matches runstatedir
from https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
Topic-rename: GNUInstallDirs-add-RUNSTATEDIR