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 -dur strace-4.5.15.orig/process.c strace-4.5.15/process.c

--- strace-4.5.15.orig/process.c	2007-01-11 23:08:38.000000000 +0100

+++ strace-4.5.15/process.c	2007-07-14 19:19:58.000000000 +0200

@@ -2679,7 +2679,6 @@

        { 4*REG_GBR,            "4*REG_GBR"                             },

        { 4*REG_MACH,           "4*REG_MACH"                            },

        { 4*REG_MACL,           "4*REG_MACL"                            },

-       { 4*REG_SYSCALL,        "4*REG_SYSCALL"                         },

        { 4*REG_FPUL,           "4*REG_FPUL"                            },

        { 4*REG_FPREG0,         "4*REG_FPREG0"                          },

        { 4*(REG_FPREG0+1),     "4*REG_FPREG1"                          },