[flang] [clang-tools-extra] [llvm] [clang] [flang] GETLOG runtime and extension implementation: get login username (PR #74628)

[Yi Wu via cfe-commits]

yi-wu-arm wrote:

accidently push the wrong branch in previous pr https://github.com/llvm/llvm-project/pull/70917

https://github.com/llvm/llvm-project/pull/74628