diff --git a/src/gs.c b/src/gs.c
index 9eddccc..bc9d2a0 100644
--- a/src/gs.c
+++ b/src/gs.c
@@ -7,6 +7,7 @@
 #include "name.h"
 #include "fail.h"
 #include "types.h"
+#include "float.h"
 
 #define gs_op gs_op_t   /* fix conflict with fortran */