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>

# Test suite config options

if EXPERIMENTAL

menu "Test suite"

config TEST_SUITE

    bool

    default n

config TEST_SUITE_GCC

    bool

    prompt "GCC test suite"

    depends on EXPERIMENTAL

    default n

    select TEST_SUITE

    help

      Select this option to install the GCC test suite in $CT_PREFIX_DIR/test_suite.

      The GCC test suite includes a collection of various toolchain tests for GCC -

      it utilizes the DejaGnu test framework.

      For some tests a network enabled target with ssh server is required.

      A helper Makefile is provided for running the tests - please see the included 

      README for information on how to run the test suite.

endmenu

endif