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>

(C) 2007 Yann E. MORIN <yann.morin.1998@anciens.enib.fr>

License: LGPL v2.1

Shut off a stupid warning: preffered-stack-boundary must be between 4 ad 12,

and 2 is not.

diff -dur glibc-2.5.orig/sysdeps/i386/Makefile glibc-2.5/sysdeps/i386/Makefile

--- glibc-2.5.orig/sysdeps/i386/Makefile	2005-03-06 01:18:16.000000000 +0100

+++ glibc-2.5/sysdeps/i386/Makefile	2007-05-27 17:49:37.000000000 +0200

@@ -36,7 +36,7 @@

 ifeq ($(subdir),csu)

 sysdep-CFLAGS += -mpreferred-stack-boundary=4

 else

-sysdep-CFLAGS += -mpreferred-stack-boundary=2

+sysdep-CFLAGS += -mpreferred-stack-boundary=4

 # Likewise, any function which calls user callbacks

 uses-callbacks += -mpreferred-stack-boundary=4

 # Likewise, any stack alignment tests