not to blindly undef isnan() and other functions that became macros in C99.
Enable use of newly grown C99 functions: strtof(), strtold(), wcstof()
Submitted by: das
to work at least for the non-hairy stuff. The main wrinkle here is that
a whole mess of include files get installed and under different names.
An earlier version of this built a shadow include tree first in the obj
directory, but this depends on the 'make includes' functionality.
More tweaking is certainly going to be needed.