buildsys remove 'install-pkg' stub

Makefile.rules

@@ -543,22 +543,6 @@ install-gaproot:
 	# LICENSE, README* ? Copy them also here? Or into some other path?
 	# TODO: also copy bin/BuildPackage.sh, as it is very useful?
 
-install-pkg:
-	@echo "Warning, 'make install-pkg' is incomplete"
-	# TODO: should we try to compiled packages? perhaps better not, leave it
-	# to the packagers, as they also need to consider build dependencies ?! If
-	# we do try it, then we may need to deal with adjusting paths and so on...
-	# we can't really install packages by any other means that copying their
-	# whole directory... One strategy to overcome this: in the future, we
-	# demand that packages which must be built using `make` also support
-	#     `make install prefix=DIR DESTDIR=dir`
-	# and/or allow packages to have a `Install(prefix, destdir)` field in
-	# their `PackageInfo.g` which contains a function that takes care of
-	# installation (e.g. by running `make install`, or by any other means).
-	# This could also be used by the PackageManager package (or perhaps we
-	# should just use PackageManager ourselves, and/or recommend it to
-	# packagers).
-
 install-headers:
 	$(INSTALL) -d -m 0755 $(DESTDIR)$(includedir)/gap
 	$(INSTALL) -m 0644 $(srcdir)/src/*.h $(DESTDIR)$(includedir)/gap