3 files changed, 170 insertions, 0 deletions
diff --git a/libc/spec/linux.td b/libc/spec/linux.td
new file mode 100644
index 00000000000..da6812f8810
--- /dev/null
+++ b/libc/spec/linux.td
@@ -0,0 +1,66 @@
+def Linux : StandardSpec<"Linux"> {
+  HeaderSpec Errno = HeaderSpec<
+      "errno.h",
+      [
+        Macro<"ENOMEDIUM">,
+        Macro<"ENOTBLK">,
+        Macro<"EMEDIUMTYPE">,
+        Macro<"EBADSLT">,
+        Macro<"ECHRNG">,
+        Macro<"ERFKILL">,
+        Macro<"EUSERS">,
+        Macro<"EBADR">,
+        Macro<"EL3HLT">,
+        Macro<"ENOTUNIQ">,
+        Macro<"EXFULL">,
+        Macro<"EHOSTDOWN">,
+        Macro<"EL3RST">,
+        Macro<"ENOPKG">,
+        Macro<"ENOCSI">,
+        Macro<"EUNATCH">,
+        Macro<"EREMCHG">,
+        Macro<"ETOOMANYREFS">,
+        Macro<"EL2HLT">,
+        Macro<"EBADFD">,
+        Macro<"EREMOTEIO">,
+        Macro<"ENAVAIL">,
+        Macro<"ELIBEXEC">,
+        Macro<"ESHUTDOWN">,
+        Macro<"ENOKEY">,
+        Macro<"ESTRPIPE">,
+        Macro<"EKEYREJECTED">,
+        Macro<"ESRMNT">,
+        Macro<"EKEYREVOKED">,
+        Macro<"EBADE">,
+        Macro<"ELIBBAD">,
+        Macro<"EISNAM">,
+        Macro<"EBFONT">,
+        Macro<"EPFNOSUPPORT">,
+        Macro<"EREMOTE">,
+        Macro<"EDEADLOCK">,
+        Macro<"ENONET">,
+        Macro<"EDOTDOT">,
+        Macro<"EKEYEXPIRED">,
+        Macro<"ELIBSCN">,
+        Macro<"ERESTART">,
+        Macro<"EBADRQC">,
+        Macro<"EUCLEAN">,
+        Macro<"ENOANO">,
+        Macro<"ELIBACC">,
+        Macro<"EHWPOISON">,
+        Macro<"ELIBMAX">,
+        Macro<"ESOCKTNOSUPPORT">,
+        Macro<"ENOTNAM">,
+        Macro<"ELNRNG">,
+        Macro<"EL2NSYNC">,
+        Macro<"EADV">,
+        Macro<"ECOMM">,
+      ],
+      [], // Types
+      []  // Functions
+  >;
+
+  let Headers = [
+    Errno,
+  ];
+}
diff --git a/libc/spec/posix.td b/libc/spec/posix.td
new file mode 100644
index 00000000000..ce7fd43aa83
--- /dev/null
+++ b/libc/spec/posix.td
@@ -0,0 +1,91 @@
+def POSIX : StandardSpec<"POSIX"> {
+  HeaderSpec Errno = HeaderSpec<
+      "errno.h",
+      [
+        Macro<"E2BIG">,
+        Macro<"EACCES">,
+        Macro<"EADDRINUSE">,
+        Macro<"EADDRNOTAVAIL">,
+        Macro<"EAFNOSUPPORT">,
+        Macro<"EAGAIN">,
+        Macro<"EALREADY">,
+        Macro<"EBADF">,
+        Macro<"EBADMSG">,
+        Macro<"EBUSY">,
+        Macro<"ECANCELED">,
+        Macro<"ECHILD">,
+        Macro<"ECONNABORTED">,
+        Macro<"ECONNREFUSED">,
+        Macro<"ECONNRESET">,
+        Macro<"EDEADLK">,
+        Macro<"EDESTADDRREQ">,
+        Macro<"EDQUOT">,
+        Macro<"EEXIST">,
+        Macro<"EFAULT">,
+        Macro<"EFBIG">,
+        Macro<"EHOSTUNREACH">,
+        Macro<"EIDRM">,
+        Macro<"EINPROGRESS">,
+        Macro<"EINTR">,
+        Macro<"EINVAL">,
+        Macro<"EIO">,
+        Macro<"EISCONN">,
+        Macro<"EISDIR">,
+        Macro<"ELOOP">,
+        Macro<"EMFILE">,
+        Macro<"EMLINK">,
+        Macro<"EMSGSIZE">,
+        Macro<"EMULTIHOP">,
+        Macro<"ENAMETOOLONG">,
+        Macro<"ENETDOWN">,
+        Macro<"ENETRESET">,
+        Macro<"ENETUNREACH">,
+        Macro<"ENFILE">,
+        Macro<"ENOBUFS">,
+        Macro<"ENODATA">,
+        Macro<"ENODEV">,
+        Macro<"ENOENT">,
+        Macro<"ENOEXEC">,
+        Macro<"ENOLCK">,
+        Macro<"ENOLINK">,
+        Macro<"ENOMEM">,
+        Macro<"ENOMSG">,
+        Macro<"ENOPROTOOPT">,
+        Macro<"ENOSPC">,
+        Macro<"ENOSR">,
+        Macro<"ENOSTR">,
+        Macro<"ENOSYS">,
+        Macro<"ENOTCONN">,
+        Macro<"ENOTDIR">,
+        Macro<"ENOTEMPTY">,
+        Macro<"ENOTRECOVERABLE">,
+        Macro<"ENOTSOCK">,
+        Macro<"ENOTSUP">,
+        Macro<"ENOTTY">,
+        Macro<"ENXIO">,
+        Macro<"EOPNOTSUPP">,
+        Macro<"EOVERFLOW">,
+        Macro<"EOWNERDEAD">,
+        Macro<"EPERM">,
+        Macro<"EPIPE">,
+        Macro<"EPROTO">,
+        Macro<"EPROTONOSUPPORT">,
+        Macro<"EPROTOTYPE">,
+        Macro<"EROFS">,
+        Macro<"ESPIPE">,
+        Macro<"ESRCH">,
+        Macro<"ESTALE">,
+        Macro<"ETIME">,
+        Macro<"ETIMEDOUT">,
+        Macro<"ETXTBSY">,
+        Macro<"EWOULDBLOCK">,
+        Macro<"EXDEV">,
+      ],
+      [], // Types
+      []  // Functions
+  >;
+
+  let Headers = [
+    Errno,
+  ];
+}
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 154214dc516..a17a3872fa2 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -170,7 +170,20 @@ def StdC : StandardSpec<"stdc"> {
       ]
   >;
 
+  HeaderSpec Errno = HeaderSpec<
+      "errno.h",
+      [
+        Macro<"errno">,
+        Macro<"EDOM">,
+        Macro<"EILSEQ">,
+        Macro<"ERANGE">,
+      ],
+      [], // Types
+      []  // Functions
+  >;
+
   let Headers = [
+    Errno,
     Math,
     String,
     StdIO,