net: fix compile warning on Windows (and others)

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/engines/net.c b/engines/net.c
index b728df1..d0f4fa0 100644
--- a/engines/net.c
+++ b/engines/net.c
@@ -481,7 +481,7 @@
 
 	if (o->nodelay && o->proto == FIO_TYPE_TCP) {
 		optval = 1;
-		if (setsockopt(f->fd, IPPROTO_TCP, TCP_NODELAY, &optval, sizeof(int)) < 0) {
+		if (setsockopt(f->fd, IPPROTO_TCP, TCP_NODELAY, (void *) &optval, sizeof(int)) < 0) {
 			log_err("fio: cannot set TCP_NODELAY option on socket (%s), disable with 'nodelay=0'\n", strerror(errno));
 			return 1;
 		}
@@ -541,7 +541,7 @@
 
 	if (o->nodelay && o->proto == FIO_TYPE_TCP) {
 		optval = 1;
-		if (setsockopt(f->fd, IPPROTO_TCP, TCP_NODELAY, &optval, sizeof(int)) < 0) {
+		if (setsockopt(f->fd, IPPROTO_TCP, TCP_NODELAY, (void *) &optval, sizeof(int)) < 0) {
 			log_err("fio: cannot set TCP_NODELAY option on socket (%s), disable with 'nodelay=0'\n", strerror(errno));
 			return 1;
 		}
@@ -767,12 +767,12 @@
 	}
 
 	opt = 1;
-	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void*)&opt, sizeof(opt)) < 0) {
+	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void *) &opt, sizeof(opt)) < 0) {
 		td_verror(td, errno, "setsockopt");
 		return 1;
 	}
 #ifdef SO_REUSEPORT
-	if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt)) < 0) {
+	if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, (void *) &opt, sizeof(opt)) < 0) {
 		td_verror(td, errno, "setsockopt");
 		return 1;
 	}