std.posix: Add missing cmsghdr and cmsg_align to compile on psp (#37154)

After testing Zig-PSP on Zig 0.17, our `http` examples fail because `std/Io/net.zig` includes `cmsghdr` and `cmsg_align`. The PSP does not support this, therefore adding the pattern here fixes our builds.

Reviewed-on: https://codeberg.org/ziglang/zig/pulls/37154
Reviewed-by: Andrew Kelley <andrew@ziglang.org>

lib/std/posix.zig

@@ -50,6 +50,8 @@ else switch (native_os) {
         pub const ino_t = u64;
         pub const IFNAMESIZE = {};
         pub const SIG = void;
+        pub const cmsghdr = void;
+        pub const cmsg_align = {};
 
         // https://github.com/pspdev/newlib/blob/9e0a073634ad73e8e088f2e071c55a9fe5d39709/newlib/libc/sys/psp/sys/dirent.h#L19
         pub const NAME_MAX = 255;