comptools: do not force build of make-3.81 unless really needed

On systems with make-3.82, we forcibly force the build and the use
of make-3.81

But some newer tools break when building with make-3.81. For example,
eglibc-3.18 breaks.

Introduce a new blind options that tools may select if they require
make-3.81. If the system does not have make-3.81, and this option is
selected, then we force the build of make-3.81. Otherwise, we leave
it to the user to decide on his own.

Note that no component selects this option for now. It will come in
later patches as we find them.

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