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>

 diff --git a/mpz/remove.c b/mpz/remove.c

 --- a/mpz/remove.c

 +++ b/mpz/remove.c

 @@ -23,7 +23,7 @@

  unsigned long int

  mpz_remove (mpz_ptr dest, mpz_srcptr src, mpz_srcptr f)

  {

 -  mpz_t fpow[40];		/* inexhaustible...until year 2020 or so */

 +  mpz_t fpow[GMP_LIMB_BITS];		/* Really MP_SIZE_T_BITS */

    mpz_t x, rem;

    unsigned long int pwr;

    int p;

 @@ -69,7 +69,7 @@

        mpz_set (dest, x);

      }

 -  pwr = (1 << p) - 1;

 +  pwr = (1L << p) - 1;

    mpz_clear (fpow[p]);

 diff --git a/mpz/remove.c b/mpz/remove.c

 --- a/mpz/remove.c

 +++ b/mpz/remove.c

 @@ -80,7 +80,7 @@

        mpz_tdiv_qr (x, rem, dest, fpow[p]);

        if (SIZ (rem) == 0)

  	{

 -	  pwr += 1 << p;

 +	  pwr += 1L << p;

  	  mpz_set (dest, x);

  	}

        mpz_clear (fpow[p]);