From c253db68caea45ee56b7d35e93bb2945b98ddf5b Mon Sep 17 00:00:00 2001
From: Ed Schouten <ed@nuxi.nl>
Date: Sat, 10 Jan 2015 09:57:33 +0100
Subject: [PATCH] Add a new compilation flag: OPENLIBM_ONLY_THREAD_SAFE.

The global signgam variable is only part of the X/Open System
Interfaces. It is not part of the POSIX base definitions nor the C
standard.

I'd rather have it disabled for my specific use-case, so introduce a new
compilation flag that we can use to disable it.
---
 src/e_gamma.c   | 6 ++++--
 src/e_gammaf.c  | 6 ++++--
 src/e_lgamma.c  | 6 ++++--
 src/e_lgammaf.c | 6 ++++--
 src/e_lgammal.c | 5 +++--
 src/openlibm.h  | 3 +++
 src/s_signgam.c | 2 ++
 7 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/src/e_gamma.c b/src/e_gamma.c
index ff7b257..3c3e97c 100644
--- a/src/e_gamma.c
+++ b/src/e_gamma.c
@@ -25,10 +25,12 @@
 
 #include "math_private.h"
 
-extern int signgam;
-
 DLLEXPORT double
 __ieee754_gamma(double x)
 {
+#ifdef OPENLIBM_ONLY_THREAD_SAFE
+	int signgam;
+#endif
+
 	return __ieee754_gamma_r(x,&signgam);
 }
diff --git a/src/e_gammaf.c b/src/e_gammaf.c
index 465efb4..1cb2c74 100644
--- a/src/e_gammaf.c
+++ b/src/e_gammaf.c
@@ -26,10 +26,12 @@
 
 #include "math_private.h"
 
-extern int signgam;
-
 DLLEXPORT float
 __ieee754_gammaf(float x)
 {
+#ifdef OPENLIBM_ONLY_THREAD_SAFE
+	int signgam;
+#endif
+
 	return __ieee754_gammaf_r(x,&signgam);
 }
diff --git a/src/e_lgamma.c b/src/e_lgamma.c
index da25f44..4dd5a0d 100644
--- a/src/e_lgamma.c
+++ b/src/e_lgamma.c
@@ -25,10 +25,12 @@
 
 #include "math_private.h"
 
-extern int signgam;
-
 DLLEXPORT double
 __ieee754_lgamma(double x)
 {
+#ifdef OPENLIBM_ONLY_THREAD_SAFE
+	int signgam;
+#endif
+
 	return __ieee754_lgamma_r(x,&signgam);
 }
diff --git a/src/e_lgammaf.c b/src/e_lgammaf.c
index 922be5a..40e7059 100644
--- a/src/e_lgammaf.c
+++ b/src/e_lgammaf.c
@@ -26,10 +26,12 @@
 
 #include "math_private.h"
 
-extern int signgam;
-
 DLLEXPORT float
 __ieee754_lgammaf(float x)
 {
+#ifdef OPENLIBM_ONLY_THREAD_SAFE
+	int signgam;
+#endif
+
 	return __ieee754_lgammaf_r(x,&signgam);
 }
diff --git a/src/e_lgammal.c b/src/e_lgammal.c
index 2e68630..5ae5761 100644
--- a/src/e_lgammal.c
+++ b/src/e_lgammal.c
@@ -4,11 +4,12 @@
 
 #include "math_private.h"
 
-extern int signgam;
-
 DLLEXPORT long double
 lgammal(long double x)
 {
+#ifdef OPENLIBM_ONLY_THREAD_SAFE
+	int signgam;
+#endif
 
 	return (lgammal_r(x, &signgam));
 }
diff --git a/src/openlibm.h b/src/openlibm.h
index 513ad4d..ca704c7 100644
--- a/src/openlibm.h
+++ b/src/openlibm.h
@@ -170,7 +170,10 @@ extern const union __nan_un {
 #define	M_SQRT1_2	0.70710678118654752440	/* 1/sqrt(2) */
 
 #define	MAXFLOAT	((float)3.40282346638528860e+38)
+
+#ifndef OPENLIBM_ONLY_THREAD_SAFE
 extern int signgam;
+#endif
 #endif /* __BSD_VISIBLE || __XSI_VISIBLE */
 
 #if __BSD_VISIBLE
diff --git a/src/s_signgam.c b/src/s_signgam.c
index 7e197a0..1557899 100644
--- a/src/s_signgam.c
+++ b/src/s_signgam.c
@@ -2,4 +2,6 @@
 
 #include "math_private.h"
 
+#ifndef OPENLIBM_ONLY_THREAD_SAFE
 int signgam = 0;
+#endif