patch 8.1.1468: the generated desktop files may be invalid

Problem:    The generated desktop files may be invalid.
Solution:   Check validity with desktop-file-validate. (Christian Brabandt,
            Will Thompson, closes #4480)
diff --git a/src/po/Makefile b/src/po/Makefile
index 6049b49..8c7066b 100644
--- a/src/po/Makefile
+++ b/src/po/Makefile
@@ -151,7 +151,7 @@
 
 clean: checkclean
 	rm -f core core.* *.old.po *.mo *.pot sjiscorr
-	rm -f LINGUAS vim.desktop gvim.desktop
+	rm -f LINGUAS vim.desktop gvim.desktop tmp_*desktop
 
 distclean: clean
 
@@ -167,13 +167,17 @@
 
 vim.desktop: vim.desktop.in $(POFILES)
 	@echo $(LANGUAGES) | tr " " "\n" |sed -e '/\./d' | sort > LINGUAS
-	$(MSGFMT) --desktop -d . --template vim.desktop.in -o vim.desktop
+	$(MSGFMT) --desktop -d . --template vim.desktop.in -o tmp_vim.desktop
 	rm -f LINGUAS
+	if command -v desktop-file-validate; then desktop-file-validate tmp_vim.desktop; fi
+	mv tmp_vim.desktop vim.desktop
 
 gvim.desktop: gvim.desktop.in $(POFILES)
 	@echo $(LANGUAGES) | tr " " "\n" |sed -e '/\./d' | sort > LINGUAS
-	$(MSGFMT) --desktop -d . --template gvim.desktop.in -o gvim.desktop
+	$(MSGFMT) --desktop -d . --template gvim.desktop.in -o tmp_gvim.desktop
 	rm -f LINGUAS
+	if command -v desktop-file-validate; then desktop-file-validate tmp_gvim.desktop; fi
+	mv tmp_gvim.desktop gvim.desktop
 
 update-po: $(LANGUAGES)
 
diff --git a/src/version.c b/src/version.c
index de5e0ab..443a114 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1468,
+/**/
     1467,
 /**/
     1466,