diff --git a/app/src/sys/unix/command.c b/app/src/sys/unix/command.c
index 64a54e71..09925c50 100644
--- a/app/src/sys/unix/command.c
+++ b/app/src/sys/unix/command.c
@@ -5,6 +5,10 @@
 // modern glibc will complain without this
 #define _DEFAULT_SOURCE
 
+#ifdef __APPLE__
+# define _DARWIN_C_SOURCE // for strdup(), strtok_r(), memset_pattern4()
+#endif
+
 #include "command.h"
 
 #include "config.h"