diff --git a/src/Intrinsic.c b/src/Intrinsic.c
index c9624ec..addcdba 100644
--- a/src/Intrinsic.c
+++ b/src/Intrinsic.c
@@ -1312,21 +1312,101 @@ static void FillInLangSubs(
     } else (void) strcpy(*rest, string);
 }
 
+
+
 /*
- * default path used if environment variable XFILESEARCHPATH
- * is not defined.  Also substitued for %D.
- * The exact value should be documented in the implementation
- * notes for any Xt implementation.
+   Return the default search path for the function
+   XtResolvePathname to use if XFILESEARCHPATH is
+   not defined.
+
+   It returns the combination the set of values which are the 6 "stems" below,
+   prepended with "/run/current-system/profile", and $GUIX_PROFILE and
+   "$HOME/.guix-profile"
+
+   These values provide the default paths where Guix/GuixSD can expect
+   to find resources for installed packages.
  */
-static const char *implementation_default_path(void)
+static const char *guix_default_path(void)
 {
-#if defined(WIN32)
-    static char xfilesearchpath[] = "";
+  static const char *search_path_default_stem[] = {
+    "/lib/X11/%L/%T/%N%C%S",
+    "/lib/X11/%l/%T/%N%C%S",
+    "/lib/X11/%T/%N%C%S",
+    "/lib/X11/%L/%T/%N%S",
+    "/lib/X11/%l/%T/%N%S",
+    "/lib/X11/%T/%N%S"
+  };
+
+#define SIZEOF_STEMS  (strlen (search_path_default_stem[0])	\
+		       + strlen (search_path_default_stem[1])	\
+		       + strlen (search_path_default_stem[2])	\
+		       + strlen (search_path_default_stem[3])	\
+		       + strlen (search_path_default_stem[4])	\
+		       + strlen (search_path_default_stem[5]))
+
+
+  int i;
+  const char *current_profile = "/run/current-system/profile";
+  char *home = getenv ("HOME");
+  char *guix_profile = getenv ("GUIX_PROFILE");
+
+  size_t bytesAllocd = SIZEOF_STEMS + 1;
+
+  /* This function is evaluated multiple times and the calling
+     code assumes that it is idempotent. So we must not allow
+     (say) a changed environment variable to cause it to return
+     something different. */
+  static char *path = NULL;
+  if (path)
+    return path;
+
+  bytesAllocd += 6 * (1 + strlen (current_profile));
+
+  if (guix_profile != NULL)
+    {
+      bytesAllocd += SIZEOF_STEMS;
+      bytesAllocd += 6 * (1 + strlen (guix_profile));
+    }
 
-    return xfilesearchpath;
-#else
-    return XFILESEARCHPATHDEFAULT;
-#endif
+  if (home != NULL)
+    {
+      bytesAllocd += SIZEOF_STEMS;
+      bytesAllocd += 6 * (1 + strlen(home) + strlen ("/.guix-profile"));
+    }
+
+  path = XtMalloc(bytesAllocd);
+  if (path == NULL) _XtAllocError(NULL);
+
+  memset (path, 0, bytesAllocd);
+
+  for (i = 0 ; i < 6 ; ++i)
+    {
+      strcat (path, current_profile);
+      strcat (path, search_path_default_stem[i]);
+      strcat (path, ":");
+    }
+
+  if (guix_profile != NULL)
+    for (i = 0 ; i < 6 ; ++i)
+      {
+	strcat (path, guix_profile);
+	strcat (path, search_path_default_stem[i]);
+	strcat (path, ":");
+      }
+
+  if (home != NULL)
+    for (i = 0 ; i < 6 ; ++i)
+      {
+	strcat (path, home);
+	strcat (path, "/.guix-profile");
+	strcat (path, search_path_default_stem[i]);
+	strcat (path, ":");
+      }
+
+  /* Remove final : */
+  path[strlen(path) - 1] = '\0';
+
+  return path;
 }
 
 
@@ -1354,7 +1434,7 @@ _XtString XtResolvePathname(
 {
     XtPerDisplay pd;
     static const char *defaultPath = NULL;
-    const char *impl_default = implementation_default_path();
+    const char *impl_default = guix_default_path();
     int idef_len = (int) strlen(impl_default);
     char *massagedPath;
     int bytesAllocd, bytesLeft;
scm,
gnu/tests/cups.scm, gnu/tests/databases.scm, gnu/tests/desktop.scm,
gnu/tests/dict.scm, gnu/tests/docker.scm, gnu/tests/file-sharing.scm,
gnu/tests/ganeti.scm, gnu/tests/guix.scm, gnu/tests/ldap.scm,
gnu/tests/linux-modules.scm,
gnu/tests/mail.scm, gnu/tests/messaging.scm, gnu/tests/monitoring.scm,
gnu/tests/networking.scm, gnu/tests/nfs.scm,
gnu/tests/package-management.scm, gnu/tests/reconfigure.scm,
gnu/tests/rsync.scm, gnu/tests/security-token.scm,
gnu/tests/singularity.scm, gnu/tests/ssh.scm, gnu/tests/telephony.scm,
gnu/tests/version-control.scm, gnu/tests/virtualization.scm,
gnu/tests/web.scm: Remove (mkdir #$output) (chdir #$output) and
pass #$output as argument to 'system-test-runner'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-09-25 18:52:05 +0200'>2021-09-25</span></td><td><a href='/guix/commit/gnu/tests/messaging.scm?id=1fb75128a5202b406622da6272bc809c46d1f439'>tests: Adjust to SRFI-64 as found in Guile 3.0.7.</a><span class='msg-avail'>...<span class='msg-tooltip'>In Guile 3.0.7, 'test-runner-current' is set to #f upon 'test-end'.
Consequently, the previous strategy, where we'd call
'test-runner-current' after 'test-end', no longer works.  Instead, set
the test runner in each test right before 'test-begin'.

* gnu/build/marionette.scm (system-test-runner): New procedure.
* gnu/tests/audio.scm (run-mpd-test): Replace (exit (= ...)) idiom
by (test-runner-current (system-test-runner)).
* gnu/tests/base.scm (run-basic-test)
(run-cleanup-test, run-mcron-test, run-nss-mdns-test): Likewise.
* gnu/tests/ci.scm (run-laminar-test): Likewise.
* gnu/tests/cups.scm (run-cups-test): Likewise.
* gnu/tests/databases.scm (run-memcached-test)
(run-postgresql-test, run-mysql-test): Likewise.
* gnu/tests/desktop.scm (run-elogind-test): Likewise.
* gnu/tests/dict.scm (run-dicod-test): Likewise.
* gnu/tests/docker.scm (run-docker-test): Likewise.
(run-docker-system-test): Likewise.
* gnu/tests/file-sharing.scm (run-transmission-daemon-test): Likewise.
* gnu/tests/ganeti.scm (run-ganeti-test): Likewise.
* gnu/tests/guix.scm (run-guix-build-coordinator-test): Likewise.
(run-guix-data-service-test): Likewise.
* gnu/tests/ldap.scm (run-ldap-test): Likewise.
* gnu/tests/linux-modules.scm (run-loadable-kernel-modules-test-base): Likewise.
* gnu/tests/mail.scm (run-opensmtpd-test)
(run-exim-test, run-dovecot-test, run-getmail-test): Likewise.
* gnu/tests/messaging.scm (run-xmpp-test)
(run-bitlbee-test, run-quassel-test): Likewise.
* gnu/tests/monitoring.scm (run-prometheus-node-exporter-server-test)
(run-zabbix-server-test): Likewise.
* gnu/tests/networking.scm (run-inetd-test, run-openvswitch-test)
(run-dhcpd-test, run-tor-test, run-iptables-test, run-ipfs-test): Likewise.
* gnu/tests/nfs.scm (run-nfs-test)
(run-nfs-server-test, run-nfs-root-fs-test): Likewise.
* gnu/tests/package-management.scm (run-nix-test): Likewise.
* gnu/tests/reconfigure.scm (run-switch-to-system-test)
(run-upgrade-services-test, run-install-bootloader-test): Likewise.
* gnu/tests/rsync.scm (run-rsync-test): Likewise.
* gnu/tests/security-token.scm (run-pcscd-test): Likewise.
* gnu/tests/singularity.scm (run-singularity-test): Likewise.
* gnu/tests/ssh.scm (run-ssh-test): Likewise.
* gnu/tests/telephony.scm (run-jami-test): Likewise.
* gnu/tests/version-control.scm (run-cgit-test): Likewise.
(run-git-http-test, run-gitolite-test, run-gitile-test): Likewise.
* gnu/tests/virtualization.scm (run-libvirt-test, run-childhurd-test): Likewise.
* gnu/tests/web.scm (run-webserver-test, run-php-fpm-test)
(run-hpcguix-web-server-test, run-tailon-test, run-patchwork-test): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>