fix(common): ensure TERM is always set with a fallback to dumb

This avoids some corner cases that some applications behave ill when
TERM is completely unset. Instead, ensure we set TERM to dumb as a
fallback, which should serve better than not having any term defined.

Signed-off-by: Levente Polyak <anthraxx@archlinux.org>

src/lib/common.sh

@@ -31,6 +31,9 @@ export PACKAGING_REPO_RELEASE_HOST=repos.archlinux.org
 export PKGBASE_MAINTAINER_URL=https://archlinux.org/packages/pkgbase-maintainer
 export AUR_URL_SSH=aur@aur.archlinux.org
 
+# ensure TERM is set with a fallback to dumb
+export TERM=${TERM:-dumb}
+
 # check if messages are to be printed using color
 if [[ -t 2 && "$TERM" != dumb ]] || [[ ${DEVTOOLS_COLOR} == always ]]; then
 	colorize