diff --git a/Python/pymath.c b/Python/pymath.c
index 5d09b4c..2749688 100644
--- a/Python/pymath.c
+++ b/Python/pymath.c
@@ -35,7 +35,7 @@
 #endif /* HAVE_HYPOT */
 
 #ifndef HAVE_COPYSIGN
-static double
+double
 copysign(double x, double y)
 {
 	/* use atan2 to distinguish -0. from 0. */