1 files changed, 1 insertions, 1 deletions
diff --git a/flip.c b/flip.c
index 7170bb4..1112443 100644
--- a/flip.c
+++ b/flip.c
@@ -9,7 +9,7 @@
 #include <assert.h>
 #include <ctype.h>
 #include <limits.h>
-#include <math.h>
+#include <tgmath.h>
 
 #include "puzzles.h"
 #include "tree234.h"