patch 9.1.0044: po Makefiles can be improved

Problem:  po Makefiles can be improved
Solution: Improve the style of the Makefiles, update
          Makefile variables, update documentation
          (RestorerZ)

closes: #13858
closes: #13857

Signed-off-by: RestorerZ <restorer@mail2k.ru>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/po/README_mingw.txt b/src/po/README_mingw.txt
index d00ba30..a7e3259 100644
--- a/src/po/README_mingw.txt
+++ b/src/po/README_mingw.txt
@@ -20,8 +20,10 @@
 First of all you must set the environment variable LANGUAGE to xx, where xx is
 the name of your language. You can do it from the command line or adding a
 line to your autoexec.bat file: set LANGUAGE=xx. You must also add your
-language to the Make_all.mak file in the lines LANGUAGES, MOFILES, AND
-POFILES.
+language to the Make_all.mak file in the lines LANGUAGES, MOFILES, POFILES,
+and CHECKFILES. If the encoding of the translation text differs from the
+default UTF-8, add a corresponding entry in MOCONVERTED, specifying the
+required encoding.
 
 If you don't have a xx.po file, you must create it with the command: