Remove a declaration of a non-existing function

Signed-off-by: Gavin Howard <gavin@yzena.com>
diff --git a/include/lang.h b/include/lang.h
index f7356c4..59173b4 100644
--- a/include/lang.h
+++ b/include/lang.h
@@ -660,17 +660,6 @@
 void
 bc_array_expand(BcVec* a, size_t len);
 
-/**
- * Compare two BcId's and return the result. Since they are just comparing the
- * names in the BcId, I return the result from strcmp() exactly. This is used by
- * maps in their binary search.
- * @param e1  The first id.
- * @param e2  The second id.
- * @return    The result of strcmp() on the BcId's names.
- */
-int
-bc_id_cmp(const BcId* e1, const BcId* e2);
-
 #if BC_ENABLED
 
 /**