cc/gcc: disable complibs if not selected

Force gcc to not link with some companion libraries when
there are not needed (because selected-out).

There is no option to tell gcc *not* to build the Graphite and/or
LTO stuff. They *will* be built if gcc finds the suitable companion
libraries. If we do not provide them, but the host has them, then
gcc *will* find them, and link with them.

Consider the following:
- host has suitable PPL and CLooG (eg. Debian Squeeze)
- user wants to build gcc>=4.4
- user de-selects GRAPHITE
- gcc will find the hosts PPL and CLooG, and will use them
- the user moves the toolchain to an older host that does
not have them (eg. Debian Lenny)
- the toolchain fails, when it was properly setup not to

So, explicitly tell gcc *not* to use unneeded companion libs.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

diff -durN gcc-3.4.6.orig/gcc/config/mips/t-linux gcc-3.4.6/gcc/config/mips/t-linux

--- gcc-3.4.6.orig/gcc/config/mips/t-linux	1970-01-01 01:00:00.000000000 +0100

+++ gcc-3.4.6/gcc/config/mips/t-linux	2007-08-15 23:08:15.000000000 +0200

@@ -0,0 +1,3 @@

+# Compile crtbegin/end with xgot so it works for both

+# normal and large GOTs.

+CRTSTUFF_T_CFLAGS = -mxgot