diff --git a/lib/std/c/darwin.zig b/lib/std/c/darwin.zig
index 6e4ef59d38..2aa05e1cc7 100644
--- a/lib/std/c/darwin.zig
+++ b/lib/std/c/darwin.zig
@@ -3867,3 +3867,4 @@ pub const MIN = struct {
 };
 
 pub extern "c" fn mincore(addr: *align(std.mem.page_size) const anyopaque, length: usize, vec: [*]u8) c_int;
+pub extern "c" fn os_proc_available_memory() usize;