Substitute all emacsclient occurrences in emacsclient.desktop

After commit "From .desktop files, reuse a frame or start a new
Emacs as required" on 2021-06-30, there are two emacsclient
occurrences for the Exec key of etc/emacsclient.desktop.
Before this change, only the first occurrence is substituted.

* Makefile.in (install-etc): Substitute all emacsclient
occurrences in emacsclient.desktop.  (Bug#68803)

Copyright-paperwork-exempt: yes

Makefile.in

@@ -859,7 +859,7 @@ install-etc:
 	rm -f $${tmp}
 	tmp=etc/emacsclient.tmpdesktop; rm -f $${tmp}; \
 	client_name=`echo emacsclient | sed '$(TRANSFORM)'`${EXEEXT}; \
-	sed -e "/^Exec=/ s|emacsclient|${bindir}/$${client_name}|" \
+	sed -e "/^Exec=/ s|emacsclient|${bindir}/$${client_name}|g" \
 	  -e "/^Icon=emacs/ s/emacs/${EMACS_NAME}/" \
 	  $(USE_STARTUP_NOTIFICATION_SED_CMD) \
 	  $(USE_WAYLAND_DISPLAY_SED_CMD) \