[flang] [clang] [flang][driver] Remove Fortain_main static library from linking stages (PR #75816)

[Andrzej Warzyński via cfe-commits]

banach-space wrote:

> Sure, I was planning to do this for the previous PR already but got distracted. Can you point me to the right place to add this? Thanks!

Somewhere here:
* https://github.com/llvm/llvm-project/blob/main/flang/docs/FlangDriver.md

I would probably create a section on building executables and just mention that 3 runtime libs will be linked auto-magically. Unless somebody uses `-fno-fortran-main` ;-) Make it as short or as long as you prefer - your contribution is greatly appreciated 🙏🏻 :) 

https://github.com/llvm/llvm-project/pull/75816