This is a combination of two patches:

1) Taken from https://salsa.debian.org/debian/libtirpc/-/raw/master/debian/patches/03-kfreebsd.diff

Description: Fix build on non Linux architectures
Author: Andreas Beckmann <anbe@debian.org>
Last-Update: 2019-09-01

2) Taken from https://salsa.debian.org/debian/libtirpc/-/raw/master/debian/patches/05-hurd-port.diff

Description: Get source building on Hurd
 - Look for <sys/user.h> before using it.
 - Define MAXHOSTNAMELEN to 64 if missing.
 - Bind sockets on Hurd like on Linux.
Author: Petter Reinholdtsen <pere@hungry.com>

--- a/src/svc_dg.c
+++ b/src/svc_dg.c
@@ -648,6 +648,7 @@
 void
 svc_dg_enable_pktinfo(int fd, const struct __rpc_sockinfo *si)
 {
+#ifdef __linux__
 	int val = 1;
 
 	switch (si->si_af) {
@@ -660,6 +661,7 @@
 		break;
 #endif
 	}
+#endif
 }
 
 /*
@@ -670,6 +672,7 @@
 int
 svc_dg_valid_pktinfo(struct msghdr *msg)
 {
+#ifdef __linux__
 	struct cmsghdr *cmsg;
 
 	if (!msg->msg_name)
@@ -716,4 +719,7 @@
 	}
 
 	return 1;
+#else
+        return 0;
+#endif
 }
--- a/src/clnt_vc.c
+++ b/src/clnt_vc.c
@@ -71,10 +71,12 @@
 #define MCALL_MSG_SIZE 24
 
 #define CMGROUP_MAX    16
-#define SCM_CREDS      0x03            /* process creds (struct cmsgcred) */
 
 #undef rpc_createerr                   /* make it clear it is a thread safe variable */
 
+#ifndef SCM_CREDS
+#define SCM_CREDS      0x03            /* process creds (struct cmsgcred) */
+
 /*
  * Credentials structure, used to verify the identity of a peer
  * process that has sent us a message. This is allocated by the
@@ -90,6 +92,7 @@
         short   cmcred_ngroups;         /* number or groups */
         gid_t   cmcred_groups[CMGROUP_MAX];     /* groups */
 };
+#endif
 
 struct cmessage {
         struct cmsghdr cmsg;
--- a/src/getpeereid.c
+++ b/src/getpeereid.c
@@ -25,9 +25,14 @@
  */
 
 
+#include "config.h"
+
 #include <sys/param.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#ifdef HAVE_SYS_USER_H
+#  include <sys/user.h>
+#endif /* HAVE_SYS_USER_H */
 
 #include <errno.h>
 #include <unistd.h>
--- a/src/getpeereid.c
+++ b/src/getpeereid.c
@@ -35,12 +36,25 @@
 int
 getpeereid(int s, uid_t *euid, gid_t *egid)
 {
+#ifndef HAVE_SYS_USER_H
+        return(-1);
+#else
+#ifdef XUCRED_VERSION
+	struct xucred uc;
+#define uid  cr_uid
+#define gid  cr_gid
+#else
 	struct ucred uc;
+#endif
 	socklen_t uclen;
 	int error;
 
 	uclen = sizeof(uc); 
+#ifdef XUCRED_VERSION
+	error = getsockopt(s, 0, LOCAL_PEERCRED, &uc, &uclen);
+#else
 	error = getsockopt(s, SOL_SOCKET, SO_PEERCRED, &uc, &uclen); /*  SCM_CREDENTIALS */
+#endif
 	if (error != 0)
 		return (error);
 	//	if (uc.cr_version != XUCRED_VERSION)
@@ -59,4 +66,5 @@
 	*euid = uc.uid;
 	*egid = uc.gid;
 	return (0);
+#endif /* HAVE_SYS_USER_H */
  }
--- a/tirpc/reentrant.h
+++ b/tirpc/reentrant.h
@@ -36,7 +36,7 @@
  * These definitions are only guaranteed to be valid on Linux. 
  */
 
-#if defined(__linux__)
+#if defined(__linux__) || defined(__GLIBC__)
 
 #include <pthread.h>
 
--- a/configure.ac
+++ b/configure.ac
@@ -93,7 +93,7 @@
 AC_PROG_LIBTOOL
 AC_HEADER_DIRENT
 AC_PREFIX_DEFAULT(/usr)
-AC_CHECK_HEADERS([arpa/inet.h fcntl.h libintl.h limits.h locale.h netdb.h netinet/in.h stddef.h stdint.h stdlib.h string.h sys/ioctl.h sys/param.h sys/socket.h sys/time.h syslog.h unistd.h features.h gssapi/gssapi_ext.h])
+AC_CHECK_HEADERS([arpa/inet.h fcntl.h libintl.h limits.h locale.h netdb.h netinet/in.h stddef.h stdint.h stdlib.h string.h sys/ioctl.h sys/param.h sys/socket.h sys/time.h syslog.h unistd.h features.h gssapi/gssapi_ext.h sys/user.h])
 AC_CHECK_LIB([pthread], [pthread_create])
 AC_CHECK_FUNCS([getrpcbyname getrpcbynumber setrpcent endrpcent getrpcent])
 
--- a/src/auth_unix.c
+++ b/src/auth_unix.c
@@ -56,6 +56,11 @@
 #include <rpc/auth.h>
 #include <rpc/auth_unix.h>
 
+/* Workaround for Hurd */
+#ifndef MAXHOSTNAMELEN
+#  define MAXHOSTNAMELEN   64
+#endif
+
 /* auth_unix.c */
 static void authunix_nextverf (AUTH *);
 static bool_t authunix_marshal (AUTH *, XDR *);
--- a/src/bindresvport.c
+++ b/src/bindresvport.c
@@ -64,7 +64,7 @@
         return bindresvport_sa(sd, (struct sockaddr *)sin);
 }
 
-#ifdef __linux__
+#if defined(__linux__) || defined(__GNU__)
 
 #define STARTPORT 600
 #define LOWPORT 512