Fix Cygwin build after 0578e87f

Fix Cygwin build after 0578e87f ("Remove some globals from
nat/windows-nat.c").  Update code under ifdef __CYGWIN__ for globals
moved to members of struct windows_process_info.
diff --git a/gdb/nat/windows-nat.c b/gdb/nat/windows-nat.c
index f681801..ca6a529 100644
--- a/gdb/nat/windows-nat.c
+++ b/gdb/nat/windows-nat.c
@@ -198,7 +198,7 @@ windows_process_info::get_exec_module_filename (char *exe_name_ret,
        to POSIX format into the destination buffer.  */
     cygwin_buf_t *pathbuf = (cygwin_buf_t *) alloca (exe_name_max_len * sizeof (cygwin_buf_t));
 
-    len = GetModuleFileNameEx (current_process_handle,
+    len = GetModuleFileNameEx (handle,
 			       dh_buf, pathbuf, exe_name_max_len);
     if (len == 0)
       error (_("Error getting executable filename: %u."),
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 6c6dea8..ab0efe7 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -884,7 +884,7 @@ windows_nat::windows_process_info::handle_output_debug_string
 	  if (!retval)
 	    retval = current_event.dwThreadId;
 	  else if ((x = (LPCVOID) (uintptr_t) strtoull (p, NULL, 0))
-		   && ReadProcessMemory (current_process_handle, x,
+		   && ReadProcessMemory (handle, x,
 					 &saved_context,
 					 __COPY_CONTEXT_SIZE, &n)
 		   && n == __COPY_CONTEXT_SIZE)