Add posix_spawn_file_actions_t and posix_spawnattr_t and tests

src/header/spawn/mod.rs

@@ -0,0 +1,25 @@
+//! `spawn.h` implementation
+//!
+//! See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/spawn.h.html>.
+
+mod file_actions;
+mod spawn_attr;
+
+use core::ffi::c_char;
+
+use crate::{
+    header::spawn::{file_actions::posix_spawn_file_actions_t, spawn_attr::posix_spawnattr_t},
+    platform::types::{c_int, pid_t},
+};
+
+#[unsafe(no_mangle)]
+pub fn posix_spawn(
+    pid: *const pid_t,
+    path: *const c_char,
+    file_actions: *const posix_spawn_file_actions_t,
+    spawn_attr: *const posix_spawnattr_t,
+    argv: *const *const c_char,
+    envp: *const *const c_char,
+) -> c_int {
+    todo!()
+}