1 files changed, 1 insertions, 1 deletions
diff --git a/blackbox.c b/blackbox.c
index 69959b6..69ec12c 100644
--- a/blackbox.c
+++ b/blackbox.c
@@ -7,7 +7,7 @@
 #include <string.h>
 #include <assert.h>
 #include <ctype.h>
-#include <math.h>
+#include <tgmath.h>
 
 #include "puzzles.h"