diff --git a/udp_processor.cc b/udp_processor.cc
index d7a098a..5a82a04 100644
--- a/udp_processor.cc
+++ b/udp_processor.cc
@@ -112,7 +112,9 @@
 
 #if defined(__MACH__)
 static const unsigned MSG_WAITFORONE = 0;
+#endif
 
+#if defined(__MACH__) || defined(__Fuchsia__)
 static int recvmmsg(int fd, struct mmsghdr *msgvec, unsigned vlen,
                     unsigned flags, struct timespec *timeout) {
   ssize_t r = recvmsg(fd, &msgvec->msg_hdr, 0);
@@ -125,7 +127,7 @@
 }
 
 int sendmmsg(int fd, struct mmsghdr *msgvec, unsigned vlen, unsigned flags) {
-  ROUGHTIME_CHECK_EQ(1, vlen);
+  ROUGHTIME_CHECK_EQ((unsigned) 1, vlen);
   ssize_t r = sendmsg(fd, &msgvec->msg_hdr, 0);
   if (r < 0) {
     return r;
diff --git a/udp_processor.h b/udp_processor.h
index d051348..2f6d6e4 100644
--- a/udp_processor.h
+++ b/udp_processor.h
@@ -25,7 +25,7 @@
 
 namespace roughtime {
 
-#if defined(__MACH__)
+#if defined(__MACH__) || defined(__Fuchsia__)
 struct mmsghdr {
   uint8_t *iov_base;
   size_t msg_len;