Extract errno macros proxy header

Author: robincaloudis

libc/hdr/CMakeLists.txt

@@ -32,6 +32,16 @@ add_proxy_header_library(
     libc.include.math
 )
 
+add_proxy_header_library(
+  errno_macros
+  HDRS
+    errno_macros.h
+  FULL_BUILD_DEPENDS
+    libc.include.errno
+    libc.include.llvm-libc-macros.error_number_macros
+    libc.include.llvm-libc-macros.generic_error_number_macros
+)
+
 add_proxy_header_library(
   fcntl_macros
   HDRS

libc/hdr/errno_macros.h

@@ -0,0 +1,26 @@
+//===-- Definition of macros from errno.h ---------------------------------===//
+//
+// 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_ERRNO_MACROS_H
+#define LLVM_LIBC_HDR_ERRNO_MACROS_H
+
+#ifdef LIBC_FULL_BUILD
+
+#ifdef __linux__
+#include "llvm-libc-macros/error-number-macros.h"
+#else // __linux__
+#include "llvm-libc-macros/generic-error-number-macros.h"
+#endif
+
+#else // Overlay mode
+
+#include <errno.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_ERRNO_MACROS_H

libc/src/errno/CMakeLists.txt

@@ -18,8 +18,6 @@ add_entrypoint_object(
   COMPILE_OPTIONS
     ${full_build_flag}
   DEPENDS
-    libc.include.errno
-    libc.include.llvm-libc-macros.error_number_macros
-    libc.include.llvm-libc-macros.generic_error_number_macros
+    libc.hdr.errno_macros
     libc.src.__support.common
 )

libc/src/errno/libc_errno.cpp

@@ -37,7 +37,7 @@ LIBC_NAMESPACE::Errno::operator int() { return __llvmlibc_errno; }
 
 #else
 // In overlay mode, we simply use the system errno.
-#include <errno.h>
+#include "hdr/errno_macros.h"
 
 void LIBC_NAMESPACE::Errno::operator=(int a) { errno = a; }
 LIBC_NAMESPACE::Errno::operator int() { return errno; }

libc/src/errno/libc_errno.h

@@ -12,8 +12,7 @@
 #include "src/__support/macros/attributes.h"
 #include "src/__support/macros/properties/architectures.h"
 
-#include <include/llvm-libc-macros/error-number-macros.h>
-#include <include/llvm-libc-macros/generic-error-number-macros.h>
+#include "hdr/errno_macros.h"
 
 // This header is to be consumed by internal implementations, in which all of
 // them should refer to `libc_errno` instead of using `errno` directly from