Ignore the local copy of config.guess and config.sub.
Support for darwin (Mac OS X).
Portability fixes.

Check for malloc.h before including it (not present on Darwin).
Check for signal.h (needed on Darwin).
Portability fix.

On Darwin, assert is defined (in assert.h) to be a macro that in turn calls __asert_rtn.  I assume that the intention here is to ensure that calls to assert() are redirected into np, rather than hitting the libc-provided implementation.

Not sure this will work, esp with library namespaces on OSX, but it compiles for now.
Portability fixes.

Make np compile for Darwin.  This provides a skeleton on which future work can be based.
Ignore build products.
Ignore install-sh (from autotools).