win: Redefine NSIG to consider SIGWINCH

Since SIGWINCH is being defined with a value above the existing NSIG,
redefine NSIG on WIN32.

PR-URL: https://github.com/libuv/libuv/pull/2032
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

include/uv/win.h

@@ -86,6 +86,14 @@ typedef struct pollfd {
 #define SIGKILL               9
 #define SIGWINCH             28
 
+/* Redefine NSIG to take SIGWINCH into consideration */
+#if defined(NSIG) && NSIG <= SIGWINCH
+# undef NSIG
+#endif
+#ifndef NSIG
+# define NSIG SIGWINCH + 1
+#endif
+
 /* The CRT defines SIGABRT_COMPAT as 6, which equals SIGABRT on many unix-like
  * platforms. However MinGW doesn't define it, so we do. */
 #ifndef SIGABRT_COMPAT

src/win/signal.c

@@ -190,7 +190,7 @@ int uv__signal_start(uv_signal_t* handle,
                             int signum,
                             int oneshot) {
   /* Test for invalid signal values. */
-  if (signum != SIGWINCH && (signum <= 0 || signum >= NSIG))
+  if (signum <= 0 || signum >= NSIG)
     return UV_EINVAL;
 
   /* Short circuit: if the signal watcher is already watching {signum} don't go