From 3f6fb5f72ad2a4a911518ab47e260089e9e4089a Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 10 Mar 2015 04:53:46 +0000
Subject: [PATCH] math.c: fix tgamma on mingw

* math.c (mingw_tgamma): tgamma(3) on mingw returns a NaN for a
  big number, not infinity.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49913 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 math.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/math.c b/math.c
index 0ce948f8e1..f66f9ff802 100644
--- a/math.c
+++ b/math.c
@@ -786,6 +786,16 @@ math_erfc(VALUE obj, VALUE x)
     return DBL2NUM(erfc(Get_Double(x)));
 }
 
+#ifdef __MINGW32__
+static inline double
+mingw_tgamma(const double d)
+{
+    const double g = tgamma(d);
+    return (isnan(g) && !signbit(d)) ? INFINITY : g;
+}
+#define tgamma(d) mingw_tgamma(d)
+#endif
+
 /*
  * call-seq:
  *    Math.gamma(x)  -> Float