diff --git a/lib/client.c b/lib/client.c
index 836203ca9..b6236a2b8 100644
--- a/lib/client.c
+++ b/lib/client.c
@@ -358,7 +358,7 @@ static void
 strtolower(char *s)
 {
 	while (*s) {
-		*s = tolower(*s);
+		*s = tolower((int)*s);
 		s++;
 	}
 }
diff --git a/lib/libwebsockets.c b/lib/libwebsockets.c
index 3e9f761a5..579763d7c 100644
--- a/lib/libwebsockets.c
+++ b/lib/libwebsockets.c
@@ -452,7 +452,7 @@ libwebsockets_get_peer_addresses(struct libwebsocket_context *context,
 	struct libwebsocket *wsi, int fd, char *name, int name_len,
 					char *rip, int rip_len)
 {
-	unsigned int len;
+	socklen_t len;
 	struct sockaddr_in sin;
 	struct hostent *host;
 	struct hostent *host1;
@@ -554,7 +554,7 @@ int lws_set_socket_options(struct libwebsocket_context *context, int fd)
 					     (const void *)&optval, optlen) < 0)
 			return 1;
 
-#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__)
+#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__CYGWIN__)
 
 		/*
 		 * didn't find a way to set these per-socket, need to
diff --git a/lib/server.c b/lib/server.c
index 46aa18290..6ad30cc81 100644
--- a/lib/server.c
+++ b/lib/server.c
@@ -126,7 +126,7 @@ int lws_server_socket_service(struct libwebsocket_context *context,
 {
 	struct libwebsocket *new_wsi;
 	int accept_fd;
-	unsigned int clilen;
+	socklen_t clilen;
 	struct sockaddr_in cli_addr;
 	int n;
 	ssize_t len;