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>

# mingw32 config options

# depends on EXPERIMENTAL

config KERNEL_mingw32

    select MINGW32

    help

      Build a toolchain targeting systems running Windows as host

choice

    bool

    prompt "Windows api version"

# Don't remove next line

# CT_INSERT_VERSION_BELOW

config W32API_V_3_14

    bool

    prompt "3.14"

config W32API_V_select

    bool

    prompt "Other version"

endchoice

config W32API_VERSION

    string

    prompt "W32 api version" if W32API_V_select

# Don't remove next line

# CT_INSERT_VERSION_STRING_BELOW

    default "3.14" if W32API_V_3_14

    help

      Enter the version number of the windows api files to use