fix: Make variable usage consistent in Makefile

[jackchenjc]

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• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
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[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[cloudxxx8]

LGTM

[codecov-commenter]

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 27.60%. Comparing base (dd1d518) to head (ce2b774).

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Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4997   +/-   ##
=======================================
  Coverage   27.60%   27.60%           
=======================================
  Files         245      245           
  Lines       17894    17894           
=======================================
  Hits         4939     4939           
  Misses      11828    11828           
  Partials     1127     1127           

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