[libc][annex_k] Add errno_t.

libc/hdr/types/CMakeLists.txt

@@ -162,6 +162,15 @@ add_proxy_header_library(
     libc.include.fcntl
 )
 
+add_proxy_header_library(
+  errno_t
+  HDRS
+    errno_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.errno_t
+    libc.include.errno
+)
+
 add_proxy_header_library(
   fenv_t
   HDRS

libc/hdr/types/errno_t.h

@@ -0,0 +1,18 @@
+//===-- Proxy for errno_t -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_HDR_TYPES_ERRNO_T_H
+#define LLVM_LIBC_HDR_TYPES_ERRNO_T_H
+
+#define LIBC_HAS_ANNEX_K
+
+#include "include/llvm-libc-types/errno_t.h"
+
+#undef LIBC_HAS_ANNEX_K
+
+#endif // LLVM_LIBC_HDR_TYPES_ERRNO_T_H

libc/include/CMakeLists.txt

@@ -302,6 +302,7 @@ add_header_macro(
   DEPENDS
     .llvm-libc-macros.generic_error_number_macros
     .llvm-libc-macros.error_number_macros
+    .llvm-libc-types.errno_t
 )
 
 add_header_macro(

libc/include/errno.h.def

@@ -33,4 +33,6 @@ __END_C_DECLS
 
 #define errno (*__llvm_libc_errno())
 
+#include "llvm-libc-types/errno_t.h"
+
 #endif // LLVM_LIBC_ERRNO_H

libc/include/llvm-libc-types/CMakeLists.txt

@@ -29,6 +29,7 @@ add_header(double_t HDR double_t.h)
 add_header(DIR HDR DIR.h)
 add_header(dev_t HDR dev_t.h)
 add_header(div_t HDR div_t.h)
+add_header(errno_t HDR errno_t.h)
 add_header(ldiv_t HDR ldiv_t.h)
 add_header(lldiv_t HDR lldiv_t.h)
 add_header(FILE HDR FILE.h)

libc/include/llvm-libc-types/errno_t.h

@@ -0,0 +1,18 @@
+//===-- Definition of type errno_t ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_INCLUDE_LLVM_LIBC_TYPES_ERRNO_T_H
+#define LLVM_LIBC_INCLUDE_LLVM_LIBC_TYPES_ERRNO_T_H
+
+#ifdef LIBC_HAS_ANNEX_K
+
+typedef int errno_t;
+
+#endif // LIBC_HAS_ANNEX_K
+
+#endif // LLVM_LIBC_INCLUDE_LLVM_LIBC_TYPES_ERRNO_T_H