6 files changed, 6 insertions, 0 deletions
diff --git a/src/math/j0f.c b/src/math/j0f.c
index 4b0ee3b7..45883dc4 100644
--- a/src/math/j0f.c
+++ b/src/math/j0f.c
@@ -13,6 +13,7 @@
  * ====================================================
  */
 
+#define _GNU_SOURCE
 #include "libm.h"
 
 static float pzerof(float), qzerof(float);
diff --git a/src/math/j1f.c b/src/math/j1f.c
index 6abde349..58875af9 100644
--- a/src/math/j1f.c
+++ b/src/math/j1f.c
@@ -13,6 +13,7 @@
  * ====================================================
  */
 
+#define _GNU_SOURCE
 #include "libm.h"
 
 static float ponef(float), qonef(float);
diff --git a/src/math/scalb.c b/src/math/scalb.c
index a54bdf2b..efe69e60 100644
--- a/src/math/scalb.c
+++ b/src/math/scalb.c
@@ -15,6 +15,7 @@
  * should use scalbn() instead.
  */
 
+#define _GNU_SOURCE
 #include <math.h>
 
 double scalb(double x, double fn)
diff --git a/src/math/scalbf.c b/src/math/scalbf.c
index 94364974..f44ed5b6 100644
--- a/src/math/scalbf.c
+++ b/src/math/scalbf.c
@@ -13,6 +13,7 @@
  * ====================================================
  */
 
+#define _GNU_SOURCE
 #include <math.h>
 
 float scalbf(float x, float fn)
diff --git a/src/math/sincos.c b/src/math/sincos.c
index 49f8a098..35b2d923 100644
--- a/src/math/sincos.c
+++ b/src/math/sincos.c
@@ -10,6 +10,7 @@
  * ====================================================
  */
 
+#define _GNU_SOURCE
 #include "libm.h"
 
 void sincos(double x, double *sin, double *cos)
diff --git a/src/math/sincosf.c b/src/math/sincosf.c
index 1b50f01c..f8ca7232 100644
--- a/src/math/sincosf.c
+++ b/src/math/sincosf.c
@@ -14,6 +14,7 @@
  * ====================================================
  */
 
+#define _GNU_SOURCE
 #include "libm.h"
 
 /* Small multiples of pi/2 rounded to double precision. */