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>

 Enable building a pure soft-float compiler without the need for a software

 floating point library.

 diff -dur gcc-4.0.4.orig/gcc/config.gcc gcc-4.0.4/gcc/config.gcc

 --- gcc-4.0.4.orig/gcc/config.gcc	2007-02-02 19:12:28.000000000 +0100

 +++ gcc-4.0.4/gcc/config.gcc	2007-02-02 19:12:07.000000000 +0100

 @@ -677,7 +677,7 @@

  		tm_defines="TARGET_BIG_ENDIAN_DEFAULT=1 $tm_defines"

  		;;

  	esac

 -	tmake_file="${tmake_file} arm/t-arm arm/t-linux"

 +	tmake_file="${tmake_file} arm/t-arm arm/t-linux arm/t-arm-elf"

  	extra_parts="crtbegin.o crtbeginS.o crtend.o crtendS.o"

  	gnu_ld=yes

  	;;