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>

 This patch is courtesy of OpenEmbedded, by Khem Raj <raj.khem@gmail.com>

 http://cgit.openembedded.org/cgit.cgi/openembedded/commit/?id=b85b779688f0abc389e3c25d06b54de8b86385c1

 Index: ltrace-0.5.3/Makefile.in

 ===================================================================

 --- ltrace-0.5.3.orig/Makefile.in	2009-10-23 22:06:08.130304691 -0700

 +++ ltrace-0.5.3/Makefile.in	2009-10-23 22:06:53.160369614 -0700

 @@ -39,6 +39,8 @@ ltrace:		main.o libltrace.a

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

  		$(AR) rcv $@ $^

 +$(OBJ):		sysdeps/sysdep.o

 +

  sysdeps/sysdep.o: dummy

  		$(MAKE) -C sysdeps/$(OS)