[flang] [clang] [flang][Driver] Let the linker fail on multiple definitions of main() (PR #73124)

[Andrzej Warzyński via cfe-commits]

================
@@ -0,0 +1,13 @@
+! RUN: %clang -x c -o %t.c-part -c %s.c-part
----------------
banach-space wrote:

Could you try `flang-new -x c` instead? It would be great if we could avoid using the `clang` binary in Flang (to avoid increasing the dependency).

https://github.com/llvm/llvm-project/pull/73124