ui: fix icon display for GTK frontend under GNOME Shell with Wayland

The icon associated with a GtkWindow is just a hint to window managers
and not all of them will honour it. Some will instead want to show the
icon listed by the .desktop file. The desktop file is located based on
the application ID, which is set using g_set_prgname. QEMU has not
historically provided a desktop file or set its app ID, so it got a
broken icon in GNOME shell, which is now fixed.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
Message-id: 20190110120047.25369-3-berrange@redhat.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

Makefile

@@ -752,6 +752,9 @@ endif
 	mkdir -p "$(DESTDIR)/$(qemu_icondir)/hicolor/scalable/apps"; \
 	$(INSTALL_DATA) $(SRC_PATH)/ui/icons/qemu.svg \
 		"$(DESTDIR)/$(qemu_icondir)/hicolor/scalable/apps/qemu.svg"
+	mkdir -p "$(DESTDIR)/$(qemu_desktopdir)"
+	$(INSTALL_DATA) $(SRC_PATH)/ui/qemu.desktop \
+		"$(DESTDIR)/$(qemu_desktopdir)/qemu.desktop"
 ifdef CONFIG_GTK
 	$(MAKE) -C po $@
 endif

configure

@@ -5746,6 +5746,7 @@ qemu_moddir=$libdir$confsuffix
 qemu_datadir=$datadir$confsuffix
 qemu_localedir="$datadir/locale"
 qemu_icondir="$datadir/icons"
+qemu_desktopdir="$datadir/applications"
 
 # We can only support ivshmem if we have eventfd
 if [ "$eventfd" = "yes" ]; then
@@ -6212,6 +6213,7 @@ fi
 echo "qemu_helperdir=$libexecdir" >> $config_host_mak
 echo "qemu_localedir=$qemu_localedir" >> $config_host_mak
 echo "qemu_icondir=$qemu_icondir" >> $config_host_mak
+echo "qemu_desktopdir=$qemu_desktopdir" >> $config_host_mak
 echo "libs_softmmu=$libs_softmmu" >> $config_host_mak
 echo "GIT=$git" >> $config_host_mak
 echo "GIT_SUBMODULES=$git_submodules" >> $config_host_mak

ui/gtk.c

@@ -2226,6 +2226,7 @@ static void gtk_display_init(DisplayState *ds, DisplayOptions *opts)
 
     theme = gtk_icon_theme_get_default();
     gtk_icon_theme_prepend_search_path(theme, CONFIG_QEMU_ICONDIR);
+    g_set_prgname("qemu");
 
     s->window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
     s->vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);

ui/qemu.desktop

+[Desktop Entry]
+Version=1.0
+Name=QEMU
+Icon=qemu
+Type=Application
+Terminal=false
+Keywords=Emulators;Virtualization;KVM;
+NoDisplay=true