Here is an excerpt from the 'changes' file describing this change:
"dtoa.c and gdtoa/gdtoaimp.h and gdtoa/misc.c: reduce Kmax, and use
MALLOC and FREE or free for huge blocks, which are possible only in
pathological cases, such as dtoa calls in mode 3 with thousands of
digits requested, or strtod() calls with thousand of digits. For the
latter case, I have an alternate approach that runs much faster
and uses less memory, but finding time to get it ready for distribution
may take a while."