Drop the OS-Specific Includes Added Outside Their Platform Guards

GLib, GTK, D-Bus and POSIX headers are only used inside platform #if blocks, which already include them. Added unconditionally at the top of the file they broke the Windows build.

src/slic3r/GUI/MediaPlayCtrl.cpp

@@ -58,7 +58,6 @@
 #include <vector>
 #include <utility>
 #include "slic3r/GUI/Jobs/UpgradeNetworkJob.hpp"
-#include <sys/types.h>
 #include <wx/mediactrl.h>
 #include <wx/panel.h>
 #include <wx/utils.h>