Fix-up r278299 for windows
Fix-up r278299 for windows

FD_SETSIZE on windows limits the number of file descriptors, rather than their individual
magnitude (the underlying implementation uses an array rather than a bitset). This meant that the
assert in the SelectHelper was incorrect, and failing all the time. Fix that.

I am not sure whether this should be #ifdef MSVC, or #ifdef WINDOWS, but my feeling is that a
more posix-conforming implementation on windows would choose the bitset implementation, so I'm
sticking with the former.

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@278500 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb