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 -durN glibc-cvs-2.9.orig/misc/syslog.c glibc-cvs-2.9/misc/syslog.c

 --- glibc-cvs-2.9.orig/misc/syslog.c	2009-06-01 10:16:50.000000000 +0200

 +++ glibc-cvs-2.9/misc/syslog.c	2009-06-01 10:17:20.000000000 +0200

 @@ -152,7 +152,7 @@

  #define	INTERNALLOG	LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID

  	/* Check for invalid bits. */

  	if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {

 -		syslog(INTERNALLOG,

 +		__syslog(INTERNALLOG,

  		    "syslog: unknown facility/priority: %x", pri);

  		pri &= LOG_PRIMASK|LOG_FACMASK;

  	}