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>

 --- strace-orig/file.c	2008/05/20 04:56:18	1.92

 +++ strace/file.c	2008/08/01 01:13:10	1.93

 @@ -28,21 +28,22 @@

   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   *

 - *	$Id: file.c,v 1.92 2008/05/20 04:56:18 roland Exp $

 + *	$Id: file.c,v 1.93 2008/08/01 01:13:10 roland Exp $

   */

  #include "defs.h"

  #include <dirent.h>

 +

  #ifdef LINUX

 -#define dirent kernel_dirent

 -#define dirent64 kernel_dirent64

 -#include <linux/types.h>

 -#include <linux/dirent.h>

 -#undef dirent

 -#undef dirent64

 +struct kernel_dirent {

 +	unsigned long   d_ino;

 +	unsigned long   d_off;

 +	unsigned short  d_reclen;

 +	char            d_name[1];

 +};

  #else

 -#define kernel_dirent dirent

 +# define kernel_dirent dirent

  #endif

  #ifdef LINUX