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>

 2008-06-07  Mike Frysinger  <vapier@gentoo.org>

 	* sysdeps/unix/sysv/linux/alpha/sys/user.h: Copy page.h definitions

 	from the kernel header to sys/user.h and remove the #include of

 	sys/user.h.

 --- a/sysdeps/unix/sysv/linux/alpha/sys/user.h

 +++ b/sysdeps/unix/sysv/linux/alpha/sys/user.h

 @@ -23,7 +23,6 @@

     only. Don't read too much into it. Don't use it for anything other

     than gdb/strace unless you know what you are doing. */

 -#include <asm/page.h>

  #include <asm/reg.h>

  struct user

 @@ -41,6 +40,9 @@ struct user

    char u_comm[32];				/* user command name */

  };

 +#define PAGE_SHIFT		13

 +#define PAGE_SIZE		(1 << PAGE_SHIFT)

 +#define PAGE_MASK		(~(PAGE_SIZE-1))

  #define NBPG			PAGE_SIZE

  #define UPAGES			1

  #define HOST_TEXT_START_ADDR	(u.start_code)