Issue #5724: Fix cmath failures on Solaris 10.
diff --git a/Python/pymath.c b/Python/pymath.c
index 6b8def9..2749688 100644
--- a/Python/pymath.c
+++ b/Python/pymath.c
@@ -1,5 +1,18 @@
#include "Python.h"
+#ifdef X87_DOUBLE_ROUNDING
+/* On x86 platforms using an x87 FPU, this function is called from the
+ Py_FORCE_DOUBLE macro (defined in pymath.h) to force a floating-point
+ number out of an 80-bit x87 FPU register and into a 64-bit memory location,
+ thus rounding from extended precision to double precision. */
+double _Py_force_double(double x)
+{
+ volatile double y;
+ y = x;
+ return y;
+}
+#endif
+
#ifndef HAVE_HYPOT
double hypot(double x, double y)
{