Document the 'dvdrom' target.

MFC after:	3 days
X-MFC-With:	r258310
Sponsored by:	The FreeBSD Foundation

share/man/man7/release.7

@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 7, 2013
+.Dd November 18, 2013
 .Dt RELEASE 7
 .Os
 .Sh NAME
@@ -230,6 +230,10 @@ When set,
 will prevent the
 .Fa doc.txz
 distribution package from being created.
+.It Va NODVD
+Set to a non-empty value to skip the
+.Cm dvdrom
+target.
 .It Va NOPORTS
 Set to a non-empty value to skip the
 .Li ports/
@@ -270,6 +274,15 @@ This target produces files called
 and
 .Pa bootonly.iso
 as its output.
+.It Cm dvdrom
+Builds installation DVD-ROM images.
+This may require the
+.Xr md 4
+(memory disk) device driver be present in the kernel
+(either by being compiled in or available as a module).
+This target produces the
+.Pa dvd1.iso
+file as its output.
 .It Cm memstick
 Builds an installation memory stick image named
 .Pa memstick.img .
@@ -302,7 +315,8 @@ Builds a bootable installation system containing all the distribution files
 packaged by the
 .Cm packagesystem
 target, and suitable for imaging by the
-.Cm cdrom
+.Cm cdrom ,
+.Cm dvdrom
 and
 .Cm memstick
 targets.