Taken from https://salsa.debian.org/debian/rpcbind/-/raw/master/debian/patches/04-610718-non-linux.patch

--- a/src/security.c
+++ b/src/security.c
@@ -63,7 +63,7 @@
 #ifndef PORTMAP_LOG_SEVERITY
 # define PORTMAP_LOG_SEVERITY LOG_INFO
 #endif
-#ifdef __linux__
+#if defined(INET6) && !defined(IPV6PORT_RESERVED)
  #define IPV6PORT_RESERVED IPPORT_RESERVED
 #endif