[Chapel Merge] Fix issues with `--incremental` compilation and build constants

Branch: refs/heads/main
Revision: 9100be41804308f78d6e481238611323d2abd069
Author: dlongnecke-cray
Link: Fix issues with `--incremental` compilation and build constants by dlongnecke-cray · Pull Request #29352 · chapel-lang/chapel · GitHub
Log Message:
Fix issues with --incremental compilation and build constants (#29352)

This PR fixes issues with --incremental compilation by adjusting code
generation of configuration constants so that they are properly added to
chpl__header.h. It supports the PR #29348.

Reviewed by @jabraham17. Thanks!

Compare: Comparing 7260caffc65bd5b0952d720d951f12e42da252d3...aa9b2aff9e04f8ff47bc3e00eceae145560a5303 · chapel-lang/chapel · GitHub

Diff:
M compiler/codegen/codegen.cpp
https://github.com/chapel-lang/chapel/pull/29352.diff