(GAWK) Persistent Memory only works on 64-bit systems?

I recently compiled up a version of the latest GAWK (*), because I wanted
to play with some of the new features (namespaces, persistent memory, etc)

However, it looks like PMA didn't get compiled in.  Here is the first line
of --version (notice the absence of the word "Avon"):

    GNU Awk 5.3.2, API 4.0, (GNU MPFR 3.1.5, GNU MP 6.1.2)

And I remembered reading somewhere that the PMA feature works on 64-bit
systems (implying that it *only* works on 64-bit systems).

So, I'm curious as to *why* this restriction?  Could someone on the dev
team (or other knowledgeable person) comment on this?

(*) On a 32-bit Linux system.

--
Alice was  something of a  handful to her  father, Theodore Roosevelt.  He was
once asked by a visiting dignitary  about parenting his spitfire of a daughter
and he  replied, "I can be  President of the  United States, or I  can control
Alice. I cannot possibly do both."