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>

 --- a/extra/scripts/unifdef.c

 +++ b/extra/scripts/unifdef.c

 @@ -206,7 +206,7 @@

  static void             error(const char *);

  static int              findsym(const char *);

  static void             flushline(bool);

 -static Linetype         getline(void);

 +static Linetype         get_line(void);

  static Linetype         ifeval(const char **);

  static void             ignoreoff(void);

  static void             ignoreon(void);

 @@ -512,7 +512,7 @@

  	for (;;) {

  		linenum++;

 -		lineval = getline();

 +		lineval = get_line();

  		trans_table[ifstate[depth]][lineval]();

  		debug("process %s -> %s depth %d",

  		    linetype_name[lineval],

 @@ -526,7 +526,7 @@

   * help from skipcomment().

   */

  static Linetype

 -getline(void)

 +get_line(void)

  {

  	const char *cp;

  	int cursym;