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 -ur gcc-4.4.1-orig/libjava/Makefile.in gcc-4.4.1/libjava/Makefile.in

 --- gcc-4.4.1-orig/libjava/Makefile.in	2009-08-04 04:12:27.000000000 -0700

 +++ gcc-4.4.1/libjava/Makefile.in	2009-09-23 22:03:15.750951483 -0700

 @@ -8874,6 +8874,9 @@

  ecjx$(EXEEXT): $(ecjx_OBJECTS) $(ecjx_DEPENDENCIES) 

  	@rm -f ecjx$(EXEEXT)

  	$(ecjx_LINK) $(ecjx_LDFLAGS) $(ecjx_OBJECTS) $(ecjx_LDADD) $(LIBS)

 +ecjx.$(OBJEXT): $(ecjx_SOURCES)

 +	@rm -f ecjx.$(OBJEXT)

 +	$(CC_FOR_BUILD) $(BUILD_CFLAGS) -c -o $@ $<

  gappletviewer$(EXEEXT): $(gappletviewer_OBJECTS) $(gappletviewer_DEPENDENCIES) 

  	@rm -f gappletviewer$(EXEEXT)

  	$(gappletviewer_LINK) $(gappletviewer_LDFLAGS) $(gappletviewer_OBJECTS) $(gappletviewer_LDADD) $(LIBS)