abuild: warn if chown, chmod or chgrp found in install scripts

abuild.in

@@ -157,6 +157,12 @@ default_sanitycheck() {
 			die "$i: install script does not match pkgname or any subpackage"
 		fi
 		[ -e "$startdir/$i" ] || die "install script $i is missing"
+		for j in chown chmod chgrp; do
+			if grep -q $j "$startdir"/$i; then
+				warning "$i: found $j"
+				warning2 "Permissions should be fixed in APKBUILD package()"
+			fi
+		done
 	done
 	
 	for i in $triggers; do