reusing mpz_t and threads

[Ian Zimmerman]

Hi, I'd like to use gmp to do infinite precision arithmetic in a
functional language.  I also like the suggestion to keep some kind of
freelist to avoid allocating and initializing new mpzs all the time.
But, I don't know what to do about thread safety.  The freelist must be
a global and is modified each time I create a new value, which is with
every expression in a functional language.  I am afraid if I have to
lock a mutex this often it will hurt performance worse than the
individual allocations would.

Is there a tested solution to this dilemma?

TIA
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