Work around GCC bug 107575

* randall.c (hardware_rand64): Add an unnecessary initialization to
work around GCC Bug 107565.  Otherwise, GCC 12.2 outputs a warning
that is a false positive.

# Please enter the commit message for your changes. Lines starting
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# Date:      Mon Nov 7 17:20:30 2022 -0800
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# On branch main
# Changes to be committed:
#	modified:   randall.c
#
