Define try_chdir everywhere

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/host_test.function b/tests/suites/host_test.function
index 736883f..d8ff49e 100644
--- a/tests/suites/host_test.function
+++ b/tests/suites/host_test.function
@@ -442,7 +442,7 @@
  *
  * Failures are silent.
  */
-static void try_chdir(const char *argv0)
+static void try_chdir_if_supported(const char *argv0)
 {
     /* We might want to allow backslash as well, for Windows. But then we also
      * need to consider chdir() vs _chdir(), and different conventions
@@ -467,6 +467,13 @@
     }
     mbedtls_free(path);
 }
+#else /* MBEDTLS_HAVE_CHDIR */
+/* No chdir() or no support for parsing argv[0] on this platform. */
+static void try_chdir_if_supported(const char *argv0)
+{
+    (void) argv0;
+    return;
+}
 #endif /* MBEDTLS_HAVE_CHDIR */
 
 /**