* 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/fork.cc

@@ -16,6 +16,8 @@ details. */
 #include <stdarg.h>
 #include <errno.h>
 #include "dll_init.h"
+#include "dtable.h"
+#include "pinfo.h"
 
 DWORD NO_COPY chunksize = 0;
 /* Timeout to wait for child to start, parent to init child, etc.  */