makedoc.c: Coverity Scan Issues

Hi

Scan reports 3 issues in makedoc.c.

  One  is a memory leak around lines 1202 to 1282 because the variable word
holds memory allocated inside nextword. The method returns without freeing
the memory.    I think adding a free() is sufficient for this.

The others are from calling realloc() and not checking for NULL around line
137. Is checking for the NULL, printing a message, and exit(1), an OK thing
to do here?

Thanks.

--joel