* winsup.h: Split out dtable definitions into separate header file.

* dtable.h: New file.
* sigproc.h: Eliminate pinfo.h usage here.  Use it in source files that need
it.

winsup/cygwin/exceptions.cc

@@ -15,6 +15,7 @@ details. */
 
 #include "exceptions.h"
 #include <imagehlp.h>
+#include "pinfo.h"
 
 char debugger_command[2 * MAX_PATH + 20];