Support rudimentary INCLUDE directive

src/include/ini.sh

     fi
 }
 
+__ini_body() {
+    #
+    # Produce mkit.ini body including INCLUDE
+    #
+    # Note: recursive includes are not supported.
+    #
+    local inc                       # file to include
+    local incre='\[INCLUDE:.*\]'    # include directive regex
+    local iline                     # include directive line
+    if iline=$(grep -m1 -x "$incre" "$MKIT_INI"); then
+        inc=${iline#*:}; inc=${inc%]}
+        grep -vx "$incre" "$inc"
+        grep -vx "$incre" "$MKIT_INI"
+    else
+        cat "$MKIT_INI"
+    fi
+}
+
 ini() {
     #
     # do ini operation
         1value) fn=__ini_greppath; limit="tail -1" ;;
         *)      die "incorrect use of \`ini()\`"
     esac
-    <"$MKIT_INI" $fn "$arg" | $limit
+    __ini_body | $fn "$arg" | $limit
 }
 
 update_version() {