1 files changed, 1 insertions, 1 deletions
diff --git a/twiddle.c b/twiddle.c
index 215d225..2c15617 100644
--- a/twiddle.c
+++ b/twiddle.c
@@ -11,7 +11,7 @@
 #include <assert.h>
 #include <ctype.h>
 #include <limits.h>
-#include <math.h>
+#include <tgmath.h>
 
 #include "puzzles.h"