diff --git a/src/w32.c b/src/w32.c
index 7a80275a7c8..086c1acfb38 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -272,7 +272,7 @@ static BOOL WINAPI revert_to_self (void);
 static int sys_access (const char *, int);
 extern void *e_malloc (size_t);
 extern int sys_select (int, SELECT_TYPE *, SELECT_TYPE *, SELECT_TYPE *,
-		       struct timespec *, sigset_t *);
+		       struct timespec *, void *);
 extern int sys_dup (int);
 
 
diff --git a/src/w32.h b/src/w32.h
index 760bb14c00d..702bb5255cd 100644
--- a/src/w32.h
+++ b/src/w32.h
@@ -25,6 +25,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <windows.h>
 
+
 /* File descriptor set emulation.  */
 
 /* MSVC runtime library has limit of 64 descriptors by default */
diff --git a/src/w32proc.c b/src/w32proc.c
index c4f1f693741..c9bc28510f7 100644
--- a/src/w32proc.c
+++ b/src/w32proc.c
@@ -72,7 +72,7 @@ extern BOOL g_b_init_compare_string_w;
 extern BOOL g_b_init_debug_break_process;
 
 int sys_select (int, SELECT_TYPE *, SELECT_TYPE *, SELECT_TYPE *,
-		struct timespec *, sigset_t *);
+		struct timespec *, void *);
 
 /* Signal handlers...SIG_DFL == 0 so this is initialized correctly.  */
 static signal_handler sig_handlers[NSIG];
@@ -849,8 +849,8 @@ alarm (int seconds)
    stream is terminated, terminates the reader thread as part of
    deleting the child_process object.
 
-   The sys_select function emulates the Posix 'pselect' function; it
-   is needed because the Windows 'select' function supports only
+   The sys_select function emulates the Posix 'pselect' functionality;
+   it is needed because the Windows 'select' function supports only
    network sockets, while Emacs expects 'pselect' to work for any file
    descriptor, including pipes and serial streams.
 
@@ -2096,7 +2096,7 @@ extern int proc_buffered_char[];
 
 int
 sys_select (int nfds, SELECT_TYPE *rfds, SELECT_TYPE *wfds, SELECT_TYPE *efds,
-	    struct timespec *timeout, sigset_t *ignored)
+	    struct timespec *timeout, void *ignored)
 {
   SELECT_TYPE orfds, owfds;
   DWORD timeout_ms, start_time;