Add missing definitions on Windows.

src/dropin.h

@@ -63,4 +63,11 @@ extern int usleep(long long usec);
 } while (0)
 #endif
 
+#ifdef HAVE_MINGW
+#define mkdir(a, b) mkdir(a)
+#ifndef SHUT_RDWR
+#define SHUT_RDWR SD_BOTH
+#endif
+#endif
+
 #endif /* __DROPIN_H__ */

src/fake-gai-errnos.h

@@ -17,3 +17,7 @@
 #ifndef EAI_FAMILY
 #define EAI_FAMILY 3
 #endif
+
+#ifndef EAI_SYSTEM
+#define EAI_SYSTEM 4
+#endif

src/tincctl.c

@@ -40,7 +40,6 @@
 #include "top.h"
 
 #ifdef HAVE_MINGW
-#define mkdir(a, b) mkdir(a)
 #define SCRIPTEXTENSION ".bat"
 #else
 #define SCRIPTEXTENSION ""