linuxcnc-uspace: use dh_install to install the appropriate 'extra' files

Author: SebKuzminsky

debian/linuxcnc.install.in

@@ -1 +1,15 @@
 debian/linuxcnc-uspace.metainfo.xml usr/share/metainfo
+
+debian/extras/etc /
+debian/extras/lib /
+
+debian/extras/usr/share/icons usr/share
+
+debian/extras/usr/share/applications/linuxcnc.desktop              usr/share/applications
+debian/extras/usr/share/applications/linuxcnc-latency.desktop      usr/share/applications
+debian/extras/usr/share/applications/linuxcnc-pncconf.desktop      usr/share/applications
+debian/extras/usr/share/applications/linuxcnc-stepconf.desktop     usr/share/applications
+
+debian/extras/usr/share/desktop-directories/linuxcnc-cnc.directory usr/share/desktop-directories
+debian/extras/usr/share/desktop-directories/linuxcnc-doc.directory usr/share/desktop-directories
+debian/extras/usr/share/desktop-directories/linuxcnc-ref.directory usr/share/desktop-directories

debian/rules.in

@@ -73,10 +73,7 @@ override_dh_auto_install-arch:
 	DESTDIR=$(DESTDIR) $(MAKE) -C src install-software
 	py3clean .
 
-	# Install all desktop files, application-menu entries, and associated
-	# icons in DESTDIR.
 	desktop-file-validate $(shell find debian/extras/ share/applications/ -name *.desktop);
-	cd debian/extras && cp -a * $(DESTDIR)
 
 	# Install G-code quick reference docs in DESTDIR.
 	# NOTE: This is arguably documentation, but it lives in the