updates for MSVC 2015's degenerate headers

Note that 'perror' moves from stdio.h to stdlib.h, and 'rename' moves
from stdio.h to io.h. Also, standard C includes move from the compiler
to the Windows SDK, which changes the base path for the include files.

include/compat/time.h

@@ -4,7 +4,11 @@
  */
 
 #ifdef _MSC_VER
+#if _MSC_VER >= 1900
+#include <../ucrt/time.h>
+#else
 #include <../include/time.h>
+#endif
 #define gmtime_r(tp, tm) ((gmtime_s((tm), (tp)) == 0) ? (tm) : NULL)
 #else
 #include_next <time.h>