Some investigating later, I've concluded that the following patch
gets NFS4 referals working again.
//Anton
--- support/export/cache.c.orig 2024-10-02 20:44:46.774673108 +0200
+++ support/export/cache.c 2024-10-02 20:44:51.966724736 +0200
@@ -34,9 +34,9 @@
#include "pseudoflavors.h"
#include "xcommon.h"
-#ifdef HAVE_JUNCTION_SUPPORT
+//#ifdef HAVE_JUNCTION_SUPPORT
#include "fsloc.h"
-#endif
+//#endif
#ifdef USE_BLKID
#include "blkid/blkid.h"
@@ -908,7 +908,7 @@
xlog(D_CALL, "nfsd_fh: found %p path %s", found, found ? found->e_path : NULL);
}
-#ifdef HAVE_JUNCTION_SUPPORT
+//#ifdef HAVE_JUNCTION_SUPPORT
static void write_fsloc(char **bp, int *blen, struct exportent *ep)
{
struct servers *servers;
@@ -975,9 +975,9 @@
qword_addint(&bp, &blen, exp->e_anongid);
qword_addint(&bp, &blen, exp->e_fsid);
-#ifdef HAVE_JUNCTION_SUPPORT
+//#ifdef HAVE_JUNCTION_SUPPORT
write_fsloc(&bp, &blen, exp);
-#endif
+//#endif
write_secinfo(&bp, &blen, exp, flag_mask);
if (exp->e_uuid == NULL || different_fs) {
char u[16];
