Add a kernel option for use when LiveCD's are being built.

This setting should be used in our own kernel patches where we need to alter
behaviour for kernels that will be used for booting on LiveCD's.
First example is siimage-no-sata.patch.

The placement of this option is quite bad, unfortunately most of the generic
Kconfig stuff is duplicated for each arch. and I decided to go for the easy
way and find a more generic file to place it in. I chose "Library routines".

Against gentoo-sources-2.4.25-r2.

- Daniel Drake <dsd@gentoo.org>

--- linux-2.4.25-gentoo-r2/lib/Config.in	2004-05-19 15:52:04.000000000 +0100
+++ linux-2.4.25-gentoo-r2-dsd/lib/Config.in	2004-05-19 16:25:32.266281936 +0100
@@ -46,4 +46,6 @@ if [ "$CONFIG_EXPERIMENTAL" = "y" -a \
    tristate 'Hotplug firmware loading support (EXPERIMENTAL)' CONFIG_FW_LOADER
 fi
 
+bool 'Compile for Gentoo LiveCD' CONFIG_GENTOO_LIVECD
+
 endmenu