Fix stak algo as --av 5, experimental algo now --av 6

options.h

@@ -38,6 +38,7 @@ enum xmr_algo_variant {
     XMR_VARIANT_AESNI_WOLF,
     XMR_VARIANT_AESNI_BMI2,
     XMR_VARIANT_LEGACY,
+    XMR_VARIANT_STAK,
     XMR_VARIANT_EXPERIMENTAL,
     XMR_VARIANT_MAX
 };