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 --git a/mpn/generic/toom44_mul.c b/mpn/generic/toom44_mul.c

 --- a/mpn/generic/toom44_mul.c

 +++ b/mpn/generic/toom44_mul.c

 @@ -116,17 +116,16 @@

    TMP_MARK;

 -  as1  = TMP_SALLOC_LIMBS (n + 1);

 -  asm1 = TMP_SALLOC_LIMBS (n + 1);

 -  as2  = TMP_SALLOC_LIMBS (n + 1);

 -  ash  = TMP_SALLOC_LIMBS (n + 1);

 -  asmh = TMP_SALLOC_LIMBS (n + 1);

 -

 -  bs1  = TMP_SALLOC_LIMBS (n + 1);

 -  bsm1 = TMP_SALLOC_LIMBS (n + 1);

 -  bs2  = TMP_SALLOC_LIMBS (n + 1);

 -  bsh  = TMP_SALLOC_LIMBS (n + 1);

 -  bsmh = TMP_SALLOC_LIMBS (n + 1);

 +  as1  = TMP_ALLOC_LIMBS (10 * n + 10);

 +  asm1 = as1  + n + 1;

 +  as2  = asm1 + n + 1;

 +  ash  = as2  + n + 1;

 +  asmh = ash  + n + 1;

 +  bs1  = asmh + n + 1;

 +  bsm1 = bs1  + n + 1;

 +  bs2  = bsm1 + n + 1;

 +  bsh  = bs2  + n + 1;

 +  bsmh = bsh  + n + 1;

    gp = pp;

    hp = pp + n + 1;