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>

--- gcc-4.1.2.orig/gcc/Makefile.in	2006-11-01 15:40:44.000000000 +0100

+++ gcc-4.1.2/gcc/Makefile.in	2007-03-04 23:34:32.000000000 +0100

@@ -2522,7 +2522,7 @@

 # FIXME: writing proper dependencies for this is a *LOT* of work.

 libbackend.o : $(OBJS-common:.o=.c) $(out_file) \

   insn-config.h insn-flags.h insn-codes.h insn-constants.h \

-  insn-attr.h  $(DATESTAMP) $(BASEVER) $(DEVPHASE)

+  insn-attr.h  $(DATESTAMP) $(BASEVER) $(DEVPHASE) gcov-iov.h

 	$(CC) $(ALL_CFLAGS) $(ALL_CPPFLAGS) \

 	  -DTARGET_NAME=\"$(target_noncanonical)\" \

 	  -DLOCALEDIR=\"$(localedir)\" \