From ea736d55f9596e79184b9b4ade439c71530e86d8 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 6 Apr 2016 05:13:29 +0000
Subject: configure.in: check lgamma_r(-0.0)

* configure.in (rb_cv_lgamma_r_m0): check if lgamma_r(-0.0)
  returns negative infinity.  [Bug #12249]
* math.c (ruby_lgamma_r): define by the configured result.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54499 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog    |  7 +++++++
 configure.in | 32 ++++++++++++++++++++++++++++++++
 math.c       |  2 +-
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 25cedeee06..53084888c9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Wed Apr  6 14:13:28 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (rb_cv_lgamma_r_m0): check if lgamma_r(-0.0)
+	  returns negative infinity.  [Bug #12249]
+
+	* math.c (ruby_lgamma_r): define by the configured result.
+
 Wed Apr  6 10:56:15 2016  Anton Davydov  <antondavydov.o@gmail.com>
 
 	* lib/logger.rb (Logger#level=): remove unnecessary local
diff --git a/configure.in b/configure.in
index b32187bee9..3454d3ae82 100644
--- a/configure.in
+++ b/configure.in
@@ -2498,6 +2498,38 @@ main(int argc, char **argv)
 ])
 AS_IF([test "x$rb_cv_atan2_inf_c99" = xyes], [AC_DEFINE(ATAN2_INF_C99)])
 
+AS_IF([test "x$ac_cv_func_lgamma_r" = xyes], [
+    AC_CACHE_CHECK(whether lgamma_r handles -0.0, rb_cv_lgamma_r_m0, [
+	AC_TRY_RUN([
+@%:@include <math.h>
+@%:@ifdef HAVE_UNISTD_H
+@%:@include <unistd.h>
+@%:@endif
+@%:@ifndef EXIT_SUCCESS
+@%:@define EXIT_SUCCESS 0
+@%:@endif
+@%:@ifndef EXIT_FAILURE
+@%:@define EXIT_FAILURE 1
+@%:@endif
+
+int
+main(int argc, char **argv)
+{
+    int sign;
+
+    if (lgamma_r(-0.0, &sign) >= 0) return EXIT_FAILURE;
+    if (sign != -1) return EXIT_FAILURE;
+    return EXIT_SUCCESS;
+}
+],
+	[rb_cv_lgamma_r_m0=yes],
+	[rb_cv_lgamma_r_m0=no],
+	[rb_cv_lgamma_r_m0=yes]
+	)
+    ])
+    AS_IF([test "x$rb_cv_lgamma_r_m0" = xno], [AC_DEFINE(LGAMMA_R_M0_FIX)])
+])
+
 # Some platform need -lrt for clock_gettime, but the other don't.
 if test x"$ac_cv_func_clock_gettime" != xyes; then
     # glibc 2.17 moves clock_* functions from librt to the main C library.
diff --git a/math.c b/math.c
index 8c16c76c3b..9ac898f0ba 100644
--- a/math.c
+++ b/math.c
@@ -750,7 +750,7 @@ ruby_tgamma(const double d)
 #define tgamma(d) ruby_tgamma(d)
 #endif
 
-#if defined __APPLE__
+#if defined LGAMMA_R_M0_FIX
 static inline double
 ruby_lgamma_r(const double d, int *sign)
 {
-- 
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