[llvm] [llvm][Support] Add UNIX socket support (PR #73603)

[via llvm-commits]

yozhu wrote:

Hit compilation errors when building LLVM for Windows:

llvm/lib/Support/raw_ostream.cpp(1018,22): error: variable has incomplete type 'struct sockaddr_un'
[CONTEXT]  1018 |   struct sockaddr_un Addr;
[CONTEXT]       |                      ^

llvm/lib/Support/raw_ostream.cpp(1077,22): error: variable has incomplete type 'struct sockaddr_un'
[CONTEXT]  1077 |   struct sockaddr_un Addr;
[CONTEXT]       |                      ^

https://github.com/llvm/llvm-project/pull/73603