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 gcc-4.2.1.orig/libstdc++-v3/include/c_std/std_cstdio.h gcc-4.2.1/libstdc++-v3/include/c_std/std_cstdio.h

 --- gcc-4.2.1.orig/libstdc++-v3/include/c_std/std_cstdio.h	2006-12-07 10:33:51.000000000 +0100

 +++ gcc-4.2.1/libstdc++-v3/include/c_std/std_cstdio.h	2007-08-03 20:33:24.000000000 +0200

 @@ -144,7 +144,7 @@

  _GLIBCXX_END_NAMESPACE

 -#if _GLIBCXX_USE_C99

 +#if _GLIBCXX_USE_C99 || defined(__UCLIBC__)

  #undef snprintf

  #undef vfscanf