+check_versions() {
+ ret=0
+
+ while read app req_ver; do
+ # We only need libtoolize from the libtool package.
+ if test "$app" = libtool; then
+ app=libtoolize
+ fi
+ # Exempt git if --no-git is in effect.
+ if test "$app" = git; then
+ $use_git || continue
+ fi
+ # Honor $APP variables ($TAR, $AUTOCONF, etc.)
+ appvar=$(echo $app | LC_ALL=C tr '[a-z]-' '[A-Z]_')
+ test "$appvar" = TAR && appvar=AMTAR
+ case $appvar in
+ GZIP) ;; # Do not use $GZIP: it contains gzip options.
+ *) eval "app=\${$appvar-$app}" ;;
+ esac
+
+ # Handle the still-experimental Automake-NG programs specially.
+ # They remain named as the mainstream Automake programs ("automake",
+ # and "aclocal") to avoid gratuitous incompatibilities with
+ # pre-existing usages (by, say, autoreconf, or custom autogen.sh
+ # scripts), but correctly identify themselves (as being part of
+ # "GNU automake-ng") when asked their version.
+ case $app in
+ automake-ng|aclocal-ng)
+ app=${app%-ng}
+ ($app --version | grep '(GNU automake-ng)') >/dev/null 2>&1 || {
+ warn_ "Error: '$app' not found or not from Automake-NG"
+ ret=1
+ continue
+ } ;;
+ esac
+ if [ "$req_ver" = "-" ]; then
+ # Merely require app to exist; not all prereq apps are well-behaved
+ # so we have to rely on $? rather than get_version.
+ if ! check_exists $app; then
+ warn_ "Error: '$app' not found"
+ ret=1
+ fi
+ else
+ # Require app to produce a new enough version string.
+ inst_ver=$(get_version $app)
+ if [ ! "$inst_ver" ]; then
+ warn_ "Error: '$app' not found"
+ ret=1
+ else
+ latest_ver=$(sort_ver $req_ver $inst_ver | cut -d' ' -f2)
+ if [ ! "$latest_ver" = "$inst_ver" ]; then
+ warnf_ '%s\n' \
+ "Error: '$app' version == $inst_ver is too old" \
+ " '$app' version >= $req_ver is required"
+ ret=1
+ fi
+ fi
+ fi
+ done
+
+ return $ret
+}