I believe the reason why we used warn() instead of error() to report
undefined symbols is because the older implementation of error() exitted
immediately. Here, we want to find as many undefined symbols as we can,
so I chose to use warn() instead of error().
Now error() does not exit immediately, so it doesn't make sense to keep
them as warnings.
Differential Revision: https://reviews.llvm.org/D38652
llvm-svn: 315131
`main` is not the only main function in Windows. You can choose one
from these four -- {w,}{WinMain,main}. There are four different entry
point functions for them, {w,}{WinMain,main}CRTStartup, respectively.
The linker needs to choose the right one depending on which `main`
function is defined.
llvm-svn: 238667
