package/usb_modeswitch: fix installation of systemd unit file

The upstream Makefile failed to detect systemd being present in some (maybe all)
builds, resulting in the unit file not being installed. Without the unit file,
the udev rules in usb_modeswitch-data don't work as expected (no modeswitch is
performed).

This commit adds a patch that modifies the Makefile to include
'$(PREFIX)/bin/systemctl' in the list of paths checked, which makes the
installation phase work as intended. I will also submit this patch upstream.

Signed-off-by: Sol Bekic <s+removethis@s-ol.nu>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/usb_modeswitch/0001-fix-systemd-detection.patch

@@ -0,0 +1,18 @@
+Modify the Makefile to include '$(PREFIX)/bin/systemctl' in the list of paths.
+This makes the udev intgeration work as intended when using systemd.
+
+Signed-off-by: Sol Bekic <s+removethis@s-ol.nu>
+
+diff --git a/Makefile b/Makefile
+index 22bd0e0..72321a4 100755
+--- a/Makefile
++++ b/Makefile
+@@ -62,7 +62,7 @@
+	install -D --mode=755 usb_modeswitch_dispatcher $(SBINDIR)/usb_modeswitch_dispatcher
+	install -d $(DESTDIR)/var/lib/usb_modeswitch
+	test -d $(UPSDIR) -a -e /sbin/initctl && install --mode=644 usb-modeswitch-upstart.conf $(UPSDIR) || test 1
+-	test -d $(SYSDIR) -a \( -e /usr/bin/systemctl -o -e /bin/systemctl \) && install --mode=644 usb_modeswitch@.service $(SYSDIR) || test 1
++	test -d $(SYSDIR) -a \( -e /usr/bin/systemctl -o -e /bin/systemctl -o -e $(PREFIX)/bin/systemctl \) && install --mode=644 usb_modeswitch@.service $(SYSDIR) || test 1
+ 
+ install: install-script
+