Add guards to user configurable macro definitions

[mborland]

Closes: #1137

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.71%. Comparing base (52be1ad) to head (7d85d73).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1138   +/-   ##
========================================
  Coverage    93.71%   93.71%           
========================================
  Files          771      772    +1     
  Lines        61166    61168    +2     
========================================
+ Hits         57321    57323    +2     
  Misses        3845     3845           

Files	Coverage Δ
test/git_issue_1137.cpp	100.00% <100.00%> (ø)

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