* winsup.h: Eliminate inclusion of most of the cygwin .h files. Use .h files

only in sources which require them.
* Makefile.in: Generate dependencies with -MD option.

winsup/cygwin/thread.cc

@@ -20,6 +20,9 @@ details. */
 #include <assert.h>
 #include <stdlib.h>
 #include <syslog.h>
+#include "thread.h"
+#include "sync.h"
+#include "sigproc.h"
 #include "pinfo.h"
 
 extern int threadsafe;