Don't force building target GMP and MPFR when a native gdb is built. Rather,
add a config knob to configure the native gdb to use or not to use GMP and
MPFR; _this_config_knob_ will force building the target GMP and MPFR only if
turned on.

/trunk/scripts/build/debug/300-gdb.sh | 2 1 1 0 +-
/trunk/config/debug/gdb.in | 21 19 2 0 +++++++++++++++++++--
2 files changed, 20 insertions(+), 3 deletions(-)

 --- gcc-4.0.0/libstdc++-v3/configure-old	2005-04-30 22:04:48.061603912 -0500

 +++ gcc-4.0.0/libstdc++-v3/configure	2005-04-30 22:06:13.678588152 -0500

 @@ -7194,6 +7194,9 @@

  cat >>conftest.$ac_ext <<_ACEOF

  /* end confdefs.h.  */

  #include <complex.h>

 +#ifdef __UCLIBC__

 +#error ugly hack to make sure configure test fails here for cross until uClibc supports the complex funcs

 +#endif

  int

  main ()

  {