chore: Fix warnings for custom postgres_## cfg flags #1410

Job	Run time
Check	2m 1s
Functional Test (MySQL)	59s
Functional Test (SQLite)	46s
Integration Test (macOS-13)	1m 52s
Build (windows-latest)	2m 35s
Build (ubuntu-latest)	1m 26s
Integration Test (ubuntu-latest)	42s
Functional Test (PostgreSQL)	1m 1s
Build (macOS-latest)	1m 3s
Build (macOS-13)	1m 42s
Integration Test (macOS-latest)	50s
	14m 57s

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