Finally used the discovered paths from ./configure in scripts/crosstool-NG.sh:
- fix Makefile to really, really not used built-in rules and variables
- have scripts/crosstool-NG.sh generated from scripts/crosstool-NG.sh.in
- create a bin-overide directory ( in ${CT_WORK_DIR}/bin ) that contains shell wrappers to the actual discovered tools

/trunk/scripts/crosstool-NG.sh.in | 27 23 4 0 +++++++++++++++++++++---
/trunk/Makefile.in | 50 48 2 0 +++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 71 insertions(+), 6 deletions(-)

 diff -durN gcc-4.2.1.orig/libstdc++-v3/configure gcc-4.2.1/libstdc++-v3/configure

 --- gcc-4.2.1.orig/libstdc++-v3/configure	2007-08-03 20:30:21.000000000 +0200

 +++ gcc-4.2.1/libstdc++-v3/configure	2007-08-03 20:33:56.000000000 +0200

 @@ -7514,6 +7514,9 @@

  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 ()

  {