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>

# Companion tools config options

if EXPERIMENTAL

menu "Companion tools"

comment "READ HELP before you say 'Y' below !!!"

config COMP_TOOLS

    bool

    prompt "Build some companion tools"

    help

      Crosstool-NG relies on some external tools to be recent enough, namely:

        m4 >= 1.4.12

        autoconf >= 2.63

        automake >= 1.10.2

        libtool >= 2.2.4

      If your system has older versions, we can build them for you,

      but you are strongly encouraged to update your system instead!

if COMP_TOOLS

config COMP_TOOLS_m4

    bool

    prompt "m4"

config COMP_TOOLS_autoconf

    bool

    prompt "autoconf"

config COMP_TOOLS_automake

    bool

    prompt "automake"

config COMP_TOOLS_libtool

    bool

    prompt "libtool"

endif

endmenu

endif