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 -ru eglibc-2_9_orig/elf/Makefile eglibc-2_9/elf/Makefile

 --- eglibc-2_9_orig/elf/Makefile	2009-01-26 07:31:40.000000000 -0800

 +++ eglibc-2_9/elf/Makefile	2009-05-06 16:52:28.000000000 -0700

 @@ -305,7 +305,7 @@

  		  $(LDFLAGS-rtld) -Wl,-z,defs -Wl,--verbose 2>&1 |	\

  		  LC_ALL=C \

  		  sed -e '/^=========/,/^=========/!d;/^=========/d'	\

 -		      -e 's/\. = 0 + SIZEOF_HEADERS;/& _begin = . - SIZEOF_HEADERS;/' \

 +		      -e 's/\. = .* + SIZEOF_HEADERS;/& _begin = . - SIZEOF_HEADERS;/' \

  		      -e 's/\. = SEGMENT_START("text-segment", 0) + SIZEOF_HEADERS;/& _begin = . - SIZEOF_HEADERS;/' \

  		  > $@.lds

  	$(LINK.o) -nostdlib -nostartfiles -shared -o $@			\