[clang] [clang][analyzer] Implement modeling of 'fputc' in the StdLibraryFunctionsChecker (PR #77435)

[Balázs Kéri via cfe-commits]

balazske wrote:

I have already a patch to add these functions: #76979. The conditions for `fputc` are not the same, this can be clarified at the other patch.

https://github.com/llvm/llvm-project/pull/77435