Rename metainfo file to appdata

gettext 0.19.7 gained support for translating appdata files, whereas
support for metainfo files was added in 0.20. These file formats are
effectively the same: as documented in the AppStream specification,
desktop applications can install files with the suffix .appdata.xml
rather than .metainfo.xml and these will still be handled correctly.

It is desirable for this project to support RHEL 7, which has gettext
0.19.8.1, so let's use the older filename.

As noted in the same section of the specification, appdata files were
previously installed to /usr/share/appdata rather than
/usr/share/metainfo, but the spec asserts that the newer metainfo path
works all the way back to RHEL 7, so we keep the newer installation
path.

Thanks to Shin-ichi TOYAMA for flagging this issue.

https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#spec-component-location

.gitignore

@@ -15,4 +15,4 @@ TuxPaint.dmg
 *.thumbs
 src/po/POTFILES.in
 src/tuxpaint.desktop
-src/org.tuxpaint.Tuxpaint.metainfo.xml
+src/org.tuxpaint.Tuxpaint.appdata.xml

Makefile

@@ -535,7 +535,7 @@ $(MOFILES): trans/%.mo: src/po/%.po
 %.desktop: %.desktop.in $(POTFILES)
 	msgfmt --desktop -d src/po --template $< -o $@
 
-%.metainfo.xml: %.metainfo.xml.in $(POTFILES)
+%.appdata.xml: %.appdata.xml.in $(POTFILES)
 	msgfmt --xml -d src/po --template $< -o $@
 
 .PHONY: translations
@@ -547,7 +547,7 @@ translations: trans
 	@echo "Install gettext to run Tux Paint in non-U.S. English modes."
 	@echo "--------------------------------------------------------------"
 else
-translations: trans $(MOFILES) src/tuxpaint.desktop src/org.tuxpaint.Tuxpaint.metainfo.xml
+translations: trans $(MOFILES) src/tuxpaint.desktop src/org.tuxpaint.Tuxpaint.appdata.xml
 endif
 
 trans:
@@ -722,7 +722,7 @@ clean:
 # are the same as they were when you installed, of course!!!
 .PHONY: uninstall
 uninstall:	uninstall-i18n
-	-rm $(METAINFO_PREFIX)/org.tuxpaint.Tuxpaint.metainfo.xml
+	-rm $(METAINFO_PREFIX)/org.tuxpaint.Tuxpaint.appdata.xml
 	-rm /usr/share/applications/tuxpaint.desktop
 	-rm /usr/share/pixmaps/tuxpaint.png
 	-rm $(ICON_PREFIX)/tuxpaint.png
@@ -939,7 +939,7 @@ install-nokia770:
 # FIXME: No way to install SVG icons using `xdg-icon-resource`
 # (see https://bugs.launchpad.net/ubuntu/+source/xdg-utils/+bug/790449)
 .PHONY: install-xdg
-install-xdg: src/tuxpaint.desktop src/org.tuxpaint.Tuxpaint.metainfo.xml
+install-xdg: src/tuxpaint.desktop src/org.tuxpaint.Tuxpaint.appdata.xml
 	@echo
 	@echo "...Installing launcher icon into desktop environment..."
 	@if [ "x$(shell which xdg-icon-resource install)" != "x" ]; then \
@@ -960,7 +960,7 @@ install-xdg: src/tuxpaint.desktop src/org.tuxpaint.Tuxpaint.metainfo.xml
 	@if [ "x$(shell which update-desktop-database)" != "x" ]; then \
 	  update-desktop-database ; \
 	fi
-	install --mode=0644 -Dt $(METAINFO_PREFIX) src/org.tuxpaint.Tuxpaint.metainfo.xml
+	install --mode=0644 -Dt $(METAINFO_PREFIX) src/org.tuxpaint.Tuxpaint.appdata.xml
 
 # Install the PNG icon (for KDE desktop, etc.)
 # and the 24-color 32x32 XPM (for other Window managers):

src/po/POTFILES.in.in

@@ -6,7 +6,7 @@ great.h
 im.c
 macos.h
 macos.m
-org.tuxpaint.Tuxpaint.metainfo.xml.in
+org.tuxpaint.Tuxpaint.appdata.xml.in
 shapes.h
 titles.h
 tools.h