cc: add options to differentiate the need for pass-1 and pass-2

In some cases, building the core pass-1 is unneeded, as the C library
will not try to build anything when installing headers, or sill not
install anything at all.

This is for example the case for newlib, wihch does not require a core
pass-1 since it builds nothing and installs no header.

This should also be the case for newer glibc-es with newer gcc-es,
which no longer require a core pass-1, since the circular dependency
glibc <-> gcc (about TLS?) has been resolved.

Reported-by: Trevor Woerner <trevor.woerner@linaro.org>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 diff -ru ltrace-0.5.3.org/Makefile.in ltrace-0.5.3/Makefile.in

 --- ltrace-0.5.3.org/Makefile.in	2011-08-21 18:55:15.000000000 +0200

 +++ ltrace-0.5.3/Makefile.in	2011-08-21 18:40:53.000000000 +0200

 @@ -39,7 +40,7 @@

  		$(CC) $(LDFLAGS) $^ $(LIBS) -o $@

  libltrace.a: 	sysdeps/sysdep.o $(OBJ)

 -		$(AR) rcv $@ $^

 +		$(AR) rscv $@ $^

  $(OBJ):		sysdeps/sysdep.o