clib2 Code

counters for "maximum amount of memory used" and "maximum number of chunks
allocated" to the current figures for these values.

- Fixed the alloca() declaration in <stdlib.h> so that software which keys
off the fact whether or not the alloca preprocessor symbol is defined
will do the right thing.

- Added an optional call-back function which can be called if alloca()
is about to return NULL, which some software does not consider.
Rather than letting such software drop into an illegal memory access
or worse, that call-back function will be invoked instead, which can
print an error message and eventually call abort().