diff --git a/generator/XDR.ml b/generator/XDR.ml
index c299c13b2..b867bdd01 100644
--- a/generator/XDR.ml
+++ b/generator/XDR.ml
@@ -50,6 +50,10 @@ let generate_xdr () =
   pr "\n";
   pr "%%#include <config.h>\n";
   pr "\n";
+  pr "%%#ifndef HAVE_XDR_UINT64_T\n";
+  pr "%%#define xdr_uint64_t xdr_int64_t\n";
+  pr "%%#endif\n";
+  pr "\n";
 
   pr "/* This has to be defined to get around a limitation in Sun's rpcgen. */\n";
   pr "typedef string guestfs_str<>;\n";
diff --git a/m4/guestfs-libraries.m4 b/m4/guestfs-libraries.m4
index 838b76ee7..4154acf53 100644
--- a/m4/guestfs-libraries.m4
+++ b/m4/guestfs-libraries.m4
@@ -196,6 +196,13 @@ PKG_CHECK_MODULES([RPC], [libtirpc], [], [
     AC_SUBST([RPC_LIBS])
 ])
 
+dnl Unsigned 64 bit ints are not available on macOS, but
+dnl the signed functions can be used instead.
+old_LIBS="$LIBS"
+LIBS="$LIBS $RPC_LIBS"
+AC_CHECK_FUNCS([xdr_uint64_t])
+LIBS="$old_LIBS"
+
 AC_CHECK_PROG([RPCGEN],[rpcgen],[rpcgen],[no])
 AM_CONDITIONAL([HAVE_RPCGEN],[test "x$RPCGEN" != "xno"])