diff --git a/lib/std/c.zig b/lib/std/c.zig
index d98dbf0cde..c33d7b35ab 100644
--- a/lib/std/c.zig
+++ b/lib/std/c.zig
@@ -59,23 +59,45 @@ pub usingnamespace switch (builtin.os.tag) {
 
 pub const whence_t = if (builtin.os.tag == .wasi) std.os.wasi.whence_t else c_int;
 
+// Unix-like systems
+pub usingnamespace switch (builtin.os.tag) {
+    .netbsd, .windows => struct {},
+    else => struct {
+        pub const DIR = opaque {};
+        pub extern "c" fn opendir(pathname: [*:0]const u8) ?*DIR;
+        pub extern "c" fn fdopendir(fd: c_int) ?*DIR;
+        pub extern "c" fn rewinddir(dp: *DIR) void;
+        pub extern "c" fn closedir(dp: *DIR) c_int;
+        pub extern "c" fn telldir(dp: *DIR) c_long;
+        pub extern "c" fn seekdir(dp: *DIR, loc: c_long) void;
+
+        pub extern "c" fn clock_gettime(clk_id: c_int, tp: *c.timespec) c_int;
+        pub extern "c" fn clock_getres(clk_id: c_int, tp: *c.timespec) c_int;
+        pub extern "c" fn gettimeofday(noalias tv: ?*c.timeval, noalias tz: ?*c.timezone) c_int;
+        pub extern "c" fn nanosleep(rqtp: *const c.timespec, rmtp: ?*c.timespec) c_int;
+
+        pub extern "c" fn getrusage(who: c_int, usage: *c.rusage) c_int;
+
+        pub extern "c" fn sched_yield() c_int;
+
+        pub extern "c" fn sigaction(sig: c_int, noalias act: ?*const c.Sigaction, noalias oact: ?*c.Sigaction) c_int;
+        pub extern "c" fn sigprocmask(how: c_int, noalias set: ?*const c.sigset_t, noalias oset: ?*c.sigset_t) c_int;
+        pub extern "c" fn sigfillset(set: ?*c.sigset_t) void;
+        pub extern "c" fn sigwait(set: ?*c.sigset_t, sig: ?*c_int) c_int;
+
+        pub extern "c" fn socket(domain: c_uint, sock_type: c_uint, protocol: c_uint) c_int;
+
+        pub extern "c" fn stat(noalias path: [*:0]const u8, noalias buf: *c.Stat) c_int;
+
+        pub extern "c" fn alarm(seconds: c_uint) c_uint;
+    },
+};
+
 pub usingnamespace switch (builtin.os.tag) {
     .netbsd, .macos, .ios, .watchos, .tvos, .windows => struct {},
     else => struct {
-        pub extern "c" fn clock_getres(clk_id: c_int, tp: *c.timespec) c_int;
-        pub extern "c" fn clock_gettime(clk_id: c_int, tp: *c.timespec) c_int;
         pub extern "c" fn fstat(fd: c.fd_t, buf: *c.Stat) c_int;
-        pub extern "c" fn getrusage(who: c_int, usage: *c.rusage) c_int;
-        pub extern "c" fn gettimeofday(noalias tv: ?*c.timeval, noalias tz: ?*c.timezone) c_int;
-        pub extern "c" fn nanosleep(rqtp: *const c.timespec, rmtp: ?*c.timespec) c_int;
-        pub extern "c" fn sched_yield() c_int;
-        pub extern "c" fn sigaction(sig: c_int, noalias act: ?*const c.Sigaction, noalias oact: ?*c.Sigaction) c_int;
-        pub extern "c" fn sigprocmask(how: c_int, noalias set: ?*const c.sigset_t, noalias oset: ?*c.sigset_t) c_int;
-        pub extern "c" fn socket(domain: c_uint, sock_type: c_uint, protocol: c_uint) c_int;
-        pub extern "c" fn stat(noalias path: [*:0]const u8, noalias buf: *c.Stat) c_int;
-        pub extern "c" fn sigfillset(set: ?*c.sigset_t) void;
-        pub extern "c" fn alarm(seconds: c_uint) c_uint;
-        pub extern "c" fn sigwait(set: ?*c.sigset_t, sig: ?*c_int) c_int;
+        pub extern "c" fn readdir(dp: *c.DIR) ?*c.dirent;
     },
 };
 
diff --git a/lib/std/c/darwin.zig b/lib/std/c/darwin.zig
index b536471a30..e44da7e1f7 100644
--- a/lib/std/c/darwin.zig
+++ b/lib/std/c/darwin.zig
@@ -62,9 +62,13 @@ const private = struct {
     /// force 64bit version.
     /// Note that this is fixed on aarch64 and no longer necessary.
     extern "c" fn @"fstatat$INODE64"(dirfd: fd_t, path_name: [*:0]const u8, buf: *Stat, flags: u32) c_int;
+
+    extern "c" fn readdir(dir: *std.c.DIR) ?*dirent;
+    extern "c" fn @"readdir$INODE64"(dir: *std.c.DIR) ?*dirent;
 };
 pub const fstat = if (native_arch == .aarch64) private.fstat else private.@"fstat$INODE64";
 pub const fstatat = if (native_arch == .aarch64) private.fstatat else private.@"fstatat$INODE64";
+pub const readdir = if (native_arch == .aarch64) private.readdir else private.@"readdir$INODE64";
 
 pub extern "c" fn mach_absolute_time() u64;
 pub extern "c" fn mach_continuous_time() u64;
@@ -696,19 +700,6 @@ pub extern "c" fn os_unfair_lock_assert_not_owner(o: os_unfair_lock_t) void;
 
 // XXX: close -> close$NOCANCEL
 // XXX: getdirentries -> _getdirentries64
-pub extern "c" fn clock_getres(clk_id: c_int, tp: *timespec) c_int;
-pub extern "c" fn clock_gettime(clk_id: c_int, tp: *timespec) c_int;
-pub extern "c" fn getrusage(who: c_int, usage: *rusage) c_int;
-pub extern "c" fn gettimeofday(noalias tv: ?*timeval, noalias tz: ?*timezone) c_int;
-pub extern "c" fn nanosleep(rqtp: *const timespec, rmtp: ?*timespec) c_int;
-pub extern "c" fn sched_yield() c_int;
-pub extern "c" fn sigaction(sig: c_int, noalias act: ?*const Sigaction, noalias oact: ?*Sigaction) c_int;
-pub extern "c" fn sigprocmask(how: c_int, noalias set: ?*const sigset_t, noalias oset: ?*sigset_t) c_int;
-pub extern "c" fn socket(domain: c_uint, sock_type: c_uint, protocol: c_uint) c_int;
-pub extern "c" fn stat(noalias path: [*:0]const u8, noalias buf: *Stat) c_int;
-pub extern "c" fn sigfillset(set: ?*sigset_t) void;
-pub extern "c" fn alarm(seconds: c_uint) c_uint;
-pub extern "c" fn sigwait(set: ?*sigset_t, sig: ?*c_int) c_int;
 
 // See: https://opensource.apple.com/source/xnu/xnu-6153.141.1/bsd/sys/_types.h.auto.html
 // TODO: audit mode_t/pid_t, should likely be u16/i32
diff --git a/lib/std/c/linux.zig b/lib/std/c/linux.zig
index 62a7d3e964..d0a3590257 100644
--- a/lib/std/c/linux.zig
+++ b/lib/std/c/linux.zig
@@ -364,3 +364,18 @@ pub const RTLD = struct {
     pub const GLOBAL = 256;
     pub const LOCAL = 0;
 };
+
+pub const dirent = struct {
+    d_ino: c_uint,
+    d_off: c_uint,
+    d_reclen: c_ushort,
+    d_type: u8,
+    d_name: [256]u8,
+};
+pub const dirent64 = struct {
+    d_ino: c_ulong,
+    d_off: c_ulong,
+    d_reclen: c_ushort,
+    d_type: u8,
+    d_name: [256]u8,
+};