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>

 Original patch from: ../4.3.2/280-c99-complex-ugly-hack.patch

 -= BEGIN original header =-

 Original patch from gentoo: gentoo/src/patchsets/gcc/4.3.1/uclibc/90_all_303-c99-complex-ugly-hack.patch

 -= END original header =-

 diff -durN gcc-4.3.3.orig/libstdc++-v3/configure gcc-4.3.3/libstdc++-v3/configure

 --- gcc-4.3.3.orig/libstdc++-v3/configure	2008-07-07 21:49:54.000000000 +0200

 +++ gcc-4.3.3/libstdc++-v3/configure	2009-01-27 22:25:39.000000000 +0100

 @@ -38935,6 +38935,9 @@

  cat >>conftest.$ac_ext <<_ACEOF

  /* end confdefs.h.  */

  #include <complex.h>

 +#ifdef __UCLIBC__

 +#error ugly hack to make sure configure test fails here for cross until uClibc supports the complex funcs

 +#endif

  int

  main ()

  {