Fix missing defs on MacOS, again...

[jpsamaroo]

Fixes #242

[codecov-commenter]

Codecov Report

Merging #252 (f5cb516) into master (9c63657) will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #252   +/-   ##
======================================
  Coverage    0.00%   0.00%           
======================================
  Files          35      35           
  Lines        2670    2670           
======================================
  Misses       2670    2670           

Impacted Files	Coverage Δ
src/utils/clock.jl	0.00% <ø> (ø)

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