[clang] [flang] [lld] [flang] Generate main only when a Fortran program statement is present (PR #89938)

[Daniel Chen via cfe-commits]

https://github.com/DanielCChen approved this pull request.

Thanks for working on this. We have quite some Fortran C-interop test cases are affected by the "duplicate main" error. 

https://github.com/llvm/llvm-project/pull/89938