diff --git a/src/c/stdlib.c b/src/c/stdlib.c
index 62e98108..a9c72392 100644
--- a/src/c/stdlib.c
+++ b/src/c/stdlib.c
@@ -4,6 +4,13 @@ long double strtold(const char *nptr, char **endptr) {
     return (long double)strtod(nptr, endptr);
 }
 
+long double relibc_compat_cpp_strtold(const char *nptr, char **endptr)
+    __asm__("_Z7strtoldPKcPPc");
+
+long double relibc_compat_cpp_strtold(const char *nptr, char **endptr) {
+    return strtold(nptr, endptr);
+}
+
 double relibc_ldtod(const long double* val) {
     return (double)(*val);
 }
diff --git a/src/header/fcntl/mod.rs b/src/header/fcntl/mod.rs
index 6a4db2fa..82484375 100644
--- a/src/header/fcntl/mod.rs
+++ b/src/header/fcntl/mod.rs
@@ -7,6 +7,7 @@ use core::num::NonZeroU64;
 use crate::{
     c_str::CStr,
     error::ResultExt,
+    header::unistd::close,
     platform::{
         Pal, Sys,
         types::{c_char, c_int, c_short, c_ulonglong, mode_t, off_t, pid_t},
@@ -74,5 +75,22 @@ pub unsafe extern "C" fn fcntl(fildes: c_int, cmd: c_int, mut __valist: ...) ->
         _ => 0,
     };
 
+    if cmd == F_DUPFD_CLOEXEC {
+        let new_fd = Sys::fcntl(fildes, F_DUPFD_CLOEXEC, arg).or_minus_one_errno();
+        if new_fd >= 0 {
+            return new_fd;
+        }
+
+        let new_fd = Sys::fcntl(fildes, F_DUPFD, arg).or_minus_one_errno();
+        if new_fd < 0 {
+            return -1;
+        }
+        if Sys::fcntl(new_fd, F_SETFD, FD_CLOEXEC as c_ulonglong).or_minus_one_errno() < 0 {
+            let _ = close(new_fd);
+            return -1;
+        }
+        return new_fd;
+    }
+
     Sys::fcntl(fildes, cmd, arg).or_minus_one_errno()
 }
diff --git a/src/header/fcntl/linux.rs b/src/header/fcntl/linux.rs
index 9a3978dc..906ad525 100644
--- a/src/header/fcntl/linux.rs
+++ b/src/header/fcntl/linux.rs
@@ -15,7 +15,7 @@ pub const O_DIRECTORY: c_int = 0x1_0000;
 pub const O_NOFOLLOW: c_int = 0x2_0000;
 pub const O_CLOEXEC: c_int = 0x8_0000;
 pub const O_PATH: c_int = 0x20_0000;
 
-pub const FD_CLOEXEC: c_int = 0x8_0000;
+pub const FD_CLOEXEC: c_int = 1;
 
 // Defined for compatibility
 pub const O_NDELAY: c_int = O_NONBLOCK;
diff --git a/src/header/mod.rs b/src/header/mod.rs
index d3a7ba75..4cdc9f1d 100644
--- a/src/header/mod.rs
+++ b/src/header/mod.rs
@@ -2,6 +2,7 @@
 
 pub mod _aio;
 pub mod _fenv;
+pub mod arpa_nameser;
 pub mod arpa_inet;
 pub mod assert;
 pub mod bits_arpainet;
@@ -66,6 +67,7 @@ pub mod pty;
 pub mod pwd;
 // TODO: re_comp.h (deprecated)
 pub mod regex;
+pub mod resolv;
 // TODO: regexp.h (deprecated)
 pub mod sched;
 // TODO: search.h
diff --git a/src/header/arpa_nameser/cbindgen.toml b/src/header/arpa_nameser/cbindgen.toml
new file mode 100644
--- /dev/null
+++ b/src/header/arpa_nameser/cbindgen.toml
@@ -0,0 +1,9 @@
+sys_includes = ["sys/types.h", "stdint.h"]
+include_guard = "_ARPA_NAMESER_H"
+trailer = """
+typedef struct HEADER HEADER;
+"""
+language = "C"
+style = "Tag"
+no_includes = true
+cpp_compat = true
diff --git a/src/header/arpa_nameser/mod.rs b/src/header/arpa_nameser/mod.rs
new file mode 100644
--- /dev/null
+++ b/src/header/arpa_nameser/mod.rs
@@ -0,0 +1,74 @@
+//! `arpa/nameser.h` compatibility surface.
+
+use crate::{
+    header::errno::EINVAL,
+    platform::{
+        ERRNO,
+        types::{c_char, c_int, c_uchar},
+    },
+};
+
+pub const HFIXEDSZ: c_int = 12;
+pub const MAXDNAME: c_int = 256;
+
+#[repr(C)]
+#[derive(Clone, Copy, Default)]
+#[allow(non_camel_case_types)]
+pub struct HEADER {
+    pub id: u16,
+    pub flags: u16,
+    pub qdcount: u16,
+    pub ancount: u16,
+    pub nscount: u16,
+    pub arcount: u16,
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn _cbindgen_export_nameser_header(header: HEADER) {
+    let _ = header;
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn dn_expand(
+    msg: *const c_uchar,
+    eomorig: *const c_uchar,
+    comp_dn: *const c_uchar,
+    exp_dn: *mut c_char,
+    length: c_int,
+) -> c_int {
+    if msg.is_null() || eomorig.is_null() || comp_dn.is_null() || exp_dn.is_null() || length <= 0 {
+        ERRNO.set(EINVAL);
+        return -1;
+    }
+
+    let mut src = comp_dn;
+    let mut out = exp_dn.cast::<u8>();
+    let end = unsafe { exp_dn.add(length as usize) }.cast::<u8>();
+    let mut consumed: isize = 0;
+    let mut first = true;
+
+    loop {
+        if src >= eomorig {
+            ERRNO.set(EINVAL);
+            return -1;
+        }
+        let len = unsafe { *src };
+        src = unsafe { src.add(1) };
+        consumed += 1;
+        if len == 0 {
+            if out >= end { ERRNO.set(EINVAL); return -1; }
+            unsafe { *out = 0 };
+            return consumed as c_int;
+        }
+        if len & 0xC0 != 0 { ERRNO.set(EINVAL); return -1; }
+        if !first {
+            if out >= end { ERRNO.set(EINVAL); return -1; }
+            unsafe { *out = b'.' };
+            out = unsafe { out.add(1) };
+        }
+        first = false;
+        if unsafe { src.add(len as usize) } > eomorig || unsafe { out.add(len as usize) } >= end { ERRNO.set(EINVAL); return -1; }
+        unsafe { core::ptr::copy_nonoverlapping(src, out, len as usize); out = out.add(len as usize); src = src.add(len as usize); }
+        consumed += len as isize;
+    }
+}
diff --git a/src/header/resolv/cbindgen.toml b/src/header/resolv/cbindgen.toml
new file mode 100644
--- /dev/null
+++ b/src/header/resolv/cbindgen.toml
@@ -0,0 +1,6 @@
+sys_includes = ["sys/types.h", "netdb.h"]
+include_guard = "_RESOLV_H"
+language = "C"
+style = "Tag"
+no_includes = true
+cpp_compat = true
diff --git a/src/header/resolv/mod.rs b/src/header/resolv/mod.rs
new file mode 100644
--- /dev/null
+++ b/src/header/resolv/mod.rs
@@ -0,0 +1,54 @@
+//! `resolv.h` bounded compatibility surface.
+
+use crate::{
+    header::{arpa_nameser::dn_expand, errno::ENOSYS, netdb},
+    platform::{
+        ERRNO,
+        types::{c_char, c_int, c_uchar},
+    },
+};
+
+pub const RES_INIT: c_int = 0x0000_0001;
+pub const RES_DEBUG: c_int = 0x0000_0002;
+pub const RES_USE_EDNS0: c_int = 0x0008_0000;
+pub const RES_USE_DNSSEC: c_int = 0x0010_0000;
+
+#[repr(C)]
+#[derive(Clone, Copy, Default)]
+#[allow(non_camel_case_types)]
+pub struct __res_state {
+    pub options: c_int,
+}
+
+pub type res_state = *mut __res_state;
+
+#[unsafe(no_mangle)]
+pub static mut _res: __res_state = __res_state { options: 0 };
+
+#[unsafe(no_mangle)]
+pub extern "C" fn _cbindgen_export_res_state(state: __res_state) {
+    let _ = state;
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn res_init() -> c_int {
+    unsafe { _res.options |= RES_INIT; }
+    0
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn res_query(_dname: *const c_char, _class: c_int, _rtype: c_int, _answer: *mut c_uchar, _anslen: c_int) -> c_int {
+    netdb::H_ERRNO.set(netdb::NO_DATA);
+    ERRNO.set(ENOSYS);
+    -1
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn res_search(dname: *const c_char, class: c_int, rtype: c_int, answer: *mut c_uchar, anslen: c_int) -> c_int {
+    unsafe { res_query(dname, class, rtype, answer, anslen) }
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn __dn_expand(msg: *const c_uchar, eomorig: *const c_uchar, comp_dn: *const c_uchar, exp_dn: *mut c_char, length: c_int) -> c_int {
+    unsafe { dn_expand(msg, eomorig, comp_dn, exp_dn, length) }
+}