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>

--- glibc-2.7/sysdeps/unix/sysv/linux/sh/sysdep.S.orig	2005-12-30 22:16:43.000000000 +0000

+++ glibc-2.7/sysdeps/unix/sysv/linux/sh/sysdep.S	2008-08-19 22:33:14.000000000 +0100

@@ -32,3 +32,13 @@

 #define __syscall_error __syscall_error_1

 #include <sysdeps/unix/sh/sysdep.S>

+

+	.data

+	.align 3

+	.globl ___fpscr_values

+	.type ___fpscr_values, @object

+	.size ___fpscr_values, 8

+___fpscr_values:

+	.long	0

+	.long	0x80000

+weak_alias (___fpscr_values, __fpscr_values)

--- glibc-2.7/sysdeps/unix/sysv/linux/sh/Versions.orig	2003-09-01 05:05:09.000000000 +0100

+++ glibc-2.7/sysdeps/unix/sysv/linux/sh/Versions	2008-08-19 22:33:14.000000000 +0100

@@ -2,6 +2,7 @@

   GLIBC_2.2 {

     # functions used in other libraries

     __xstat64; __fxstat64; __lxstat64;

+    __fpscr_values;

     # a*

     alphasort64;