1 files changed, 1 insertions, 1 deletions
diff --git a/latin.h b/latin.h
index dbea6e4..4ec6954 100644
--- a/latin.h
+++ b/latin.h
@@ -8,7 +8,7 @@ typedef unsigned char digit;
 /* --- Solver structures, definitions --- */
 
 #ifdef STANDALONE_SOLVER
-int solver_show_working, solver_recurse_depth;
+extern int solver_show_working, solver_recurse_depth;
 #endif
 
 struct latin_solver {