3 files changed, 3 insertions, 0 deletions
diff --git a/src/math/lgamma.c b/src/math/lgamma.c
index d12462b9..9af7eee4 100644
--- a/src/math/lgamma.c
+++ b/src/math/lgamma.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include "libm.h"
 
 double lgamma(double x)
diff --git a/src/math/lgammaf.c b/src/math/lgammaf.c
index f50f2379..aed98ba4 100644
--- a/src/math/lgammaf.c
+++ b/src/math/lgammaf.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include "libm.h"
 
 float lgammaf(float x)
diff --git a/src/math/lgammal.c b/src/math/lgammal.c
index 603477c9..a33707ad 100644
--- a/src/math/lgammal.c
+++ b/src/math/lgammal.c
@@ -85,6 +85,7 @@
  *
  */
 
+#define _GNU_SOURCE
 #include "libm.h"
 
 long double lgammal(long double x)