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/configure ltrace-0.5.3/configure

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

+++ ltrace-0.5.3/configure	2011-08-21 18:54:46.000000000 +0200

@@ -15,8 +15,12 @@

 echo $PACKAGE_VERSION

 echo -n "checking HOST_OS... "

-HOST_OS=$( uname -s )

-if [ "$HOST_OS" = "Linux" ]

+if [ -z "$HOST_OS" ] ; then

+  HOST_OS=$( uname -s )

+else

+  echo -n "using preset: "

+fi

+if [ "$HOST_OS" = "Linux" -o "$HOST_OS" = "linux" ]

 then

   HOST_OS="linux-gnu"

 fi