Some pokenav work

src/pokenav_unk_2.c

@@ -0,0 +1,18 @@
+#include "global.h"
+#include "gym_leader_rematch.h"
+#include "pokenav.h"
+
+bool32 sub_81C98D4(void)
+{
+    s32 i;
+
+    for (i = 0; i < REMATCH_TABLE_ENTRIES; i++)
+    {
+        if (sub_81CB0C8(i) == gMapHeader.regionMapSectionId
+         && sub_81CAE08(i)
+         && gSaveBlock1Ptr->trainerRematches[i])
+            return TRUE;
+    }
+
+    return FALSE;
+}