runtime(lang): improve makefiles, add clean rule, fix typo (#13856)

Signed-off-by: RestorerZ <restorer@mail2k.ru>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/lang/Makefile b/runtime/lang/Makefile
index 9ce56b4e..d5f2ed6 100644
--- a/runtime/lang/Makefile
+++ b/runtime/lang/Makefile
@@ -5,6 +5,8 @@
 
 SED = LANG=C sed
 
+.PHONY: all clean
+
 all: $(CONVERTED)
 
 
@@ -30,7 +32,7 @@
 	iconv -f UTF-8 -t ISO-8859-2 $< | \
 		$(SED) -e 's/scriptencoding utf-8/scriptencoding iso-8859-2/' \
 			-e 's/" Original translations/" Generated from $<, DO NOT EDIT/' \
-			-e 's/\(" Menu Translations:.*\)(.*)/\1(ISO8859-2)/' \
+			-e 's/\(" Menu Translations:.*\)(.*)/\1(ISO-8859-2)/' \
 			> $@
 
 # Convert menu_cs_cz.utf-8.vim to create menu_czech_czech_republic.1250.vim.
@@ -226,3 +228,7 @@
 		$(SED) -e 's/scriptencoding cp1250/scriptencoding iso-8859-2/' \
 			-e 's/" Original translations/" Generated from $<, DO NOT EDIT/' \
 			> $@
+
+clean:
+	for G in $(CONVERTED); do if [ -f $$G ]; then rm -f $$G; fi; done
+#	-rm -f $(CONVERTED)