File 1399-erts-Fix-compile-error-in-zlib-zconf.h.patch of Package erlang

From d4614d4262dcbc65e1bc86d76f3ed5c336a651ad Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Thu, 26 Feb 2026 18:08:45 +0100
Subject: [PATCH 1/2] erts: Fix compile error in zlib/zconf.h

zlib/zconf.h:450:5: error: 'HAVE_STDARG_H' is not defined, evaluates to 0 [-Werror,-Wundef]

when building with either
* --enable-builtin-zlib
* without installed zlib
* with installed zlib >= 1.3.1.2
---
 erts/emulator/beam/dist.h            |  2 +-
 erts/emulator/beam/erl_bif_chksum.c  |  2 +-
 erts/emulator/beam/erl_bif_re.c      |  2 +-
 erts/emulator/beam/erl_zlib.h        | 19 +++++++++++++++++++
 erts/emulator/nifs/common/zlib_nif.c |  3 ++-
 5 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/erts/emulator/beam/dist.h b/erts/emulator/beam/dist.h
index 766d2f9487..96a0d010b4 100644
--- a/erts/emulator/beam/dist.h
+++ b/erts/emulator/beam/dist.h
@@ -25,7 +25,7 @@
 
 #include "erl_process.h"
 #include "erl_node_tables.h"
-#include "zlib.h"
+#include "erl_zlib.h"
 
 #define DFLAG_PUBLISHED               ((Uint64)0x01)
 #define DFLAG_ATOM_CACHE              ((Uint64)0x02)
diff --git a/erts/emulator/beam/erl_bif_chksum.c b/erts/emulator/beam/erl_bif_chksum.c
index a09675e355..e7181e6bc4 100644
--- a/erts/emulator/beam/erl_bif_chksum.c
+++ b/erts/emulator/beam/erl_bif_chksum.c
@@ -31,7 +31,7 @@
 #include "bif.h"
 #include "erl_binary.h"
 #include "big.h"
-#include "zlib.h"
+#include "erl_zlib.h"
 #include "erl_md5.h"
 
 
diff --git a/erts/emulator/beam/erl_zlib.h b/erts/emulator/beam/erl_zlib.h
index 6167add102..10f72331a0 100644
--- a/erts/emulator/beam/erl_zlib.h
+++ b/erts/emulator/beam/erl_zlib.h
@@ -23,8 +23,27 @@
 /* A sparse wrapper interface around zlib with erts memory allocation. 
 */
 
+/* Workaround to make zlib.h compile with -Werror=undef */
+#ifndef HAVE_UNISTD_H
+#  define HAVE_UNISTD_H 0
+#  define HAVE_UNISTD_H__UNDEF
+#endif
+#ifndef HAVE_STDARG_H
+#  define HAVE_STDARG_H 0
+#  define HAVE_STDARG_H__UNDEF
+#endif
+
 #include <zlib.h>
 
+#ifdef HAVE_UNISTD_H__UNDEF
+#  undef HAVE_UNISTD_H
+#  undef HAVE_UNISTD_H__UNDEF
+#endif
+#ifdef HAVE_STDARG_H__UNDEF
+#  undef HAVE_STDARG_H
+#  undef HAVE_STDARG_H__UNDEF
+#endif
+
 
 /* Initialize zalloc, zfree and opaque of a z_stream
 */
diff --git a/erts/emulator/nifs/common/zlib_nif.c b/erts/emulator/nifs/common/zlib_nif.c
index 6b8df9f139..14750c9bdf 100644
--- a/erts/emulator/nifs/common/zlib_nif.c
+++ b/erts/emulator/nifs/common/zlib_nif.c
@@ -24,7 +24,8 @@
 #define STATIC_ERLANG_NIF 1
 
 #include <stdio.h>
-#include <zlib.h>
+
+#include "erl_zlib.h"
 
 #include "erl_nif.h"
 #include "config.h"
-- 
2.51.0