diff --git a/examples/particles.c b/examples/particles.c
index baafe826..7a896a62 100644
--- a/examples/particles.c
+++ b/examples/particles.c
@@ -24,6 +24,8 @@
 //
 //========================================================================
 
+#define _GNU_SOURCE
+
 #if defined(_MSC_VER)
  // Make MS math.h define M_PI
  #define _USE_MATH_DEFINES
diff --git a/src/posix_time.c b/src/posix_time.c
index 4d7bd7ce..2d2b1561 100644
--- a/src/posix_time.c
+++ b/src/posix_time.c
@@ -25,6 +25,8 @@
 //
 //========================================================================
 
+#define _GNU_SOURCE
+
 #include "internal.h"
 
 #if defined(GLFW_BUILD_POSIX_TIMER)
diff --git a/src/wl_init.c b/src/wl_init.c
index 76054bc6..cba68bad 100644
--- a/src/wl_init.c
+++ b/src/wl_init.c
@@ -24,6 +24,8 @@
 //
 //========================================================================
 
+#define _GNU_SOURCE
+
 #include "internal.h"
 
 #if defined(_GLFW_WAYLAND)