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-4.4.4.orig/libstdc++-v3/include/c_global/cstdio gcc-4.4.4/libstdc++-v3/include/c_global/cstdio

 --- gcc-4.4.4.orig/libstdc++-v3/include/c_global/cstdio	2009-04-10 01:23:07.000000000 +0200

 +++ gcc-4.4.4/libstdc++-v3/include/c_global/cstdio	2010-05-16 19:37:06.000000000 +0200

 @@ -139,7 +139,7 @@

  _GLIBCXX_END_NAMESPACE

 -#if _GLIBCXX_USE_C99

 +#if _GLIBCXX_USE_C99 || defined __UCLIBC__

  #undef snprintf

  #undef vfscanf