Include the full version number in the directory paths installed.
Change the version string so that it does not break 'make', and so that it has no '/' (it would be a hell if installed directories would mirror the SVN branches... :-/ )
Do not use implicit rules for the Makefile.
Simplify and enc=hance the --local test to refuse (un)installing.
Double-quotes variables, they are based on user input.
Eye-candy in the 'compile' and install messages.

/trunk/configure | 26 14 12 0 ++++++++++---------
/trunk/Makefile.in | 83 45 38 0 +++++++++++++++++++++++++++++++++---------------------------
2 files changed, 59 insertions(+), 50 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 ()

  {