The closing brace for the CSV format branch was inside #ifndef WIN32, so the preprocessor removed it on Windows and broke the brace structure, causing bogus errors around main() with -Werror.

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Link to the related 3160:

Describe changes:

fix(tests/unit): fix MinGW build in serializeProtoUnitTest

The closing brace for the CSV format branch was inside #ifndef WIN32, so
the preprocessor removed it on Windows and broke the brace structure,
causing bogus errors around main() with -Werror.