diff --git a/vlib/builtin/cfns.c.v b/vlib/builtin/cfns.c.v
index 3559c18ce1..5147a29c76 100644
--- a/vlib/builtin/cfns.c.v
+++ b/vlib/builtin/cfns.c.v
@@ -54,7 +54,7 @@ fn C.isdigit(c int) bool
 fn C.popen(c &char, t &char) voidptr
 
 // <libproc.h>
-pub fn C.proc_pidpath(int, voidptr, int) int
+fn C.proc_pidpath(int, voidptr, int) int
 
 fn C.realpath(const_path &char, resolved_path &char) &char
 
diff --git a/vlib/os/os_darwin.c.v b/vlib/os/os_darwin.c.v
index 010044a82f..d161a43f73 100644
--- a/vlib/os/os_darwin.c.v
+++ b/vlib/os/os_darwin.c.v
@@ -3,6 +3,8 @@
 // that can be found in the LICENSE file.
 module os
 
+#include <libproc.h>
+
 pub const sys_write = 4
 pub const sys_open = 5
 pub const sys_close = 6