Support for storing perf value in GS
diff --git a/honggfuzz.c b/honggfuzz.c
index de1dc21..6a7d7b8 100644
--- a/honggfuzz.c
+++ b/honggfuzz.c
@@ -210,6 +210,9 @@
             case 'e':
                 hfuzz.dynFileMethod |= _HF_DYNFILE_UNIQUE_EDGE_COUNT;
                 break;
+            case 'f':
+                hfuzz.dynFileMethod |= _HF_DYNFILE_CUSTOM;
+                break;
             default:
                 LOGMSG(l_ERROR, "Unknown -D mode");
                 usage(EXIT_FAILURE);