diff --git a/src/utilities/upm_utilities.c b/src/utilities/upm_utilities.c
index 578d24d6..2cce14e2 100644
--- a/src/utilities/upm_utilities.c
+++ b/src/utilities/upm_utilities.c
@@ -23,6 +23,10 @@
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+#ifndef _POSIX_C_SOURCE
+// We need at least 199309L for nanosleep()
+# define _POSIX_C_SOURCE 200809L
+#endif
 #include <time.h>
 #include <errno.h>
 #include <upm_platform.h>