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 -durN duma_2_5_12.orig/Makefile duma_2_5_12/Makefile

 --- duma_2_5_12.orig/Makefile	2007-09-07 21:57:45.000000000 +0200

 +++ duma_2_5_12/Makefile	2007-09-07 21:58:35.000000000 +0200

 @@ -231,9 +231,13 @@

  	dumatest.c tstheap.c thread-test.c testmt.c dumatestpp.cpp testoperators.cpp \

  	createconf.c

 -OBJECTS = dumapp.o duma.o sem_inc.o print.o

 +OBJECTS = duma.o sem_inc.o print.o

 +SO_OBJECTS = duma_so.o sem_inc_so.o print_so.o

 -SO_OBJECTS = dumapp_so.o duma_so.o sem_inc_so.o print_so.o

 +ifeq ($(DUMA_CPP),1)

 +OBJECTS += dumapp.o

 +SO_OBJECTS += dumapp_so.o

 +endif

  all:	libduma.a tstheap$(EXEPOSTFIX) dumatest$(EXEPOSTFIX) thread-test$(EXEPOSTFIX) testmt$(EXEPOSTFIX) dumatestpp$(EXEPOSTFIX) testoperators$(EXEPOSTFIX) $(DUMA_DYN_DEPS)

  	@ $(ECHOLF)