basic: include stddef.h since we use NULL in header

diff --git a/src/basic/copy.h b/src/basic/copy.h
index 843d2d7c985c081252c0278a2cfb28b50862b899..cf2efd8e7bba37073db0ec4a2613a82f0992d7c3 100644 (file)
--- a/src/basic/copy.h
+++ b/src/basic/copy.h
@@ -4,6 +4,7 @@
 #include <fcntl.h>
 #include <inttypes.h>
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <sys/stat.h>
 #include <sys/types.h>