Fix remaining issues found by depend-pkalgs
diff --git a/tests/suites/test_suite_x509write.function b/tests/suites/test_suite_x509write.function
index ca76e86..62f82e8 100644
--- a/tests/suites/test_suite_x509write.function
+++ b/tests/suites/test_suite_x509write.function
@@ -130,6 +130,7 @@
     TEST_ASSERT( mbedtls_pk_parse_keyfile( &issuer_key, issuer_key_file,
                                          issuer_pwd ) == 0 );
 
+#if defined(MBEDTLS_RSA_C)
     /* For RSA PK contexts, create a copy as an alternative RSA context. */
     if( rsa_alt == 1 && mbedtls_pk_get_type( &issuer_key ) == MBEDTLS_PK_RSA )
     {
@@ -141,6 +142,9 @@
 
         key = &issuer_key_alt;
     }
+#else
+    (void) rsa_alt;
+#endif
 
     TEST_ASSERT( mbedtls_mpi_read_string( &serial, 10, serial_str ) == 0 );