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 -Narup uClibc-0.9.30.1.orig/libc/inet/getaddrinfo.c uClibc-0.9.30.1/libc/inet/getaddrinfo.c

 --- uClibc-0.9.30.1.orig/libc/inet/getaddrinfo.c	2009-02-26 21:49:14.000000000 +0900

 +++ uClibc-0.9.30.1/libc/inet/getaddrinfo.c	2009-03-06 00:59:23.000000000 +0900

 @@ -187,6 +187,8 @@ static unsigned __check_pf(void)

  		}

  		for (runp = ifa; runp != NULL; runp = runp->ifa_next) {

 +			if (runp->ifa_addr == NULL)

 +				continue;

  #if defined __UCLIBC_HAS_IPV4__

  			if (runp->ifa_addr->sa_family == PF_INET)

  				seen |= SEEN_IPV4;