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>

 Original patch from Gentoo.

 -= BEGIN original header =-

 -= END original header =-

 diff -durN uClibc-0.9.30.orig/libc/sysdeps/linux/arm/bits/uClibc_arch_features.h uClibc-0.9.30/libc/sysdeps/linux/arm/bits/uClibc_arch_features.h

 --- uClibc-0.9.30.orig/libc/sysdeps/linux/arm/bits/uClibc_arch_features.h	2008-09-25 10:50:56.000000000 +0200

 +++ uClibc-0.9.30/libc/sysdeps/linux/arm/bits/uClibc_arch_features.h	2009-02-07 09:57:59.000000000 +0100

 @@ -39,4 +39,8 @@

  /* define if target supports IEEE signed zero floats */

  #define __UCLIBC_HAVE_SIGNED_ZERO__

 +#ifdef __ARM_EABI__

 +# define __UCLIBC_TRUNCATE64_HAS_4_ARGS__

 +#endif

 +

  #endif /* _BITS_UCLIBC_ARCH_FEATURES_H */