allow EPM_BACKEND and SERV_BACKEND to force backend to use

bin/epm-sh-functions

@@ -701,6 +701,11 @@ set_pm_type()
     set_target_pkg_env
 
 # override package manager detection result
+if [ -n "$EPM_BACKEND" ] ; then
+    PMTYPE=$EPM_BACKEND
+    return
+fi
+# obsoleted
 if [ -n "$FORCEPM" ] ; then
     PMTYPE=$FORCEPM
     return

bin/serv

@@ -61,6 +61,8 @@ case "$DISTRCONTROL" in
 esac
 
 # override system control detection result
+[ -n "$SERV_BACKEND" ] && CMD="$SERV_BACKEND"
+# obsoleted
 [ -n "$FORCESERVICE" ] && CMD="$FORCESERVICE"
 
 SERVICETYPE="$CMD"