runanki.system: fix prefix at install time

Currently the Makefile lets you choose your own PREFIX, but
the installed runanki.system always hardcodes the prefix as /usr.

Fix runanki.system at install time to install into the designated
PREFIX.

.gitignore

@@ -7,3 +7,4 @@
 aqt/forms
 locale
 .idea
+tools/runanki.system

Makefile

@@ -9,6 +9,8 @@ install:
 	rm -rf ${DESTDIR}${PREFIX}/share/anki
 	mkdir -p ${DESTDIR}${PREFIX}/share/anki
 	cp -av * ${DESTDIR}${PREFIX}/share/anki/
+	sed -e 's:@PREFIX@:${PREFIX}:' tools/runanki.system.in > tools/runanki.system
+	chmod 755 tools/runanki.system
 	cd ${DESTDIR}${PREFIX}/share/anki && (\
 	mv tools/runanki.system ${DESTDIR}${PREFIX}/local/bin/anki;\
 	test -d ${DESTDIR}${PREFIX}/share/pixmaps &&\

tools/runanki.system.in

@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 
 import sys
-sys.path.append("/usr/share/anki")
+sys.path.append("@PREFIX@/share/anki")
 
 import aqt
 aqt.run()