'grep -q' is not portable -> don't use it.

diff --git a/documentation/PACKAGING b/documentation/PACKAGING
index ab13b25..2028c62 100644
--- a/documentation/PACKAGING
+++ b/documentation/PACKAGING

@@ -448,7 +448,7 @@
 
 The post-install script:
 
-	if ! grep -q /usr/X11R6/lib/wine /etc/ld.so.conf; then
+	if ! grep /usr/X11R6/lib/wine /etc/ld.so.conf &gt;/dev/null; then
 	    echo "/usr/X11R6/lib/wine" &gt;&gt; /etc/ld.so.conf
 	fi
 	/sbin/ldconfig