diff --git a/Modules/mathmodule.c b/Modules/mathmodule.c
index 5d9fe5a..9eaeff1 100644
--- a/Modules/mathmodule.c
+++ b/Modules/mathmodule.c
@@ -77,7 +77,7 @@
 #endif /* !defined(HAVE_ERF) || !defined(HAVE_ERFC) */
 
 static double
-sinpi(double x)
+m_sinpi(double x)
 {
     double y, r;
     int n;
@@ -305,7 +305,7 @@
        integer. */
     if (absx > 200.0) {
         if (x < 0.0) {
-            return 0.0/sinpi(x);
+            return 0.0/m_sinpi(x);
         }
         else {
             errno = ERANGE;
@@ -329,7 +329,7 @@
     }
     z = z * lanczos_g / y;
     if (x < 0.0) {
-        r = -pi / sinpi(absx) / absx * exp(y) / lanczos_sum(absx);
+        r = -pi / m_sinpi(absx) / absx * exp(y) / lanczos_sum(absx);
         r -= z * r;
         if (absx < 140.0) {
             r /= pow(y, absx - 0.5);
@@ -400,7 +400,7 @@
     r += (absx - 0.5) * (log(absx + lanczos_g - 0.5) - 1);
     if (x < 0.0)
         /* Use reflection formula to get value for negative x. */
-        r = logpi - log(fabs(sinpi(absx))) - log(absx) - r;
+        r = logpi - log(fabs(m_sinpi(absx))) - log(absx) - r;
     if (Py_IS_INFINITY(r))
         errno = ERANGE;
     return r;