cc/gcc: add option to compile against static libstdc++, for gcc-4.4 and newer

Idea and know-how taken from CodeSourcery build script.

Normal build:
$ ldd arm-unknown-linux-uclibcgnueabi-gcc
linux-gate.so.1 => (0xb77f3000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xb76e8000)
libc.so.6 => /lib/i686/cmov/libc.so.6 (0xb75a1000)
libm.so.6 => /lib/i686/cmov/libm.so.6 (0xb757a000)
/lib/ld-linux.so.2 (0xb77f4000)
libgcc_s.so.1 => /lib/libgcc_s.so.1 (0xb755c000)

CC_STATIC_LIBSTDCXX=y:
$ ldd arm-unknown-linux-uclibcgnueabi-gcc
linux-gate.so.1 => (0xb7843000)
libc.so.6 => /lib/i686/cmov/libc.so.6 (0xb76e6000)
/lib/ld-linux.so.2 (0xb7844000)

I made CC_STATIC_LIBSTDCXX default=y since I think
it is always desirable.

Signed-off-by: Johannes Stezenbach <js@sig21.net>

 22 May 2010 - Titus von Boxberg

 Prerequisites and instructions for using ct-ng for building a cross toolchain on FreeBSD as host.

 0) Tested on FreeBSD 8.0

 1) Install (at least) the following ports

    archivers/lzma

    textproc/gsed

    devel/gmake

    devel/patch

    shells/bash

    devel/bison

    lang/gawk

    devel/automake110

    ftp/wget

    Of course, you should have /usr/local/bin in your PATH.

 2) run ct-ng's configure with the following tool configuration:

    ./configure --with-sed=/usr/local/bin/gsed --with-make=/usr/local/bin/gmake \

    --with-patch=/usr/local/bin/gpatch

    [...other configure parameters as you like...]

 3) proceed as described in general documentation

    but use gmake instead of make