From 817bbc0c6d3596a06ab5374dba6d0ad298397040 Mon Sep 17 00:00:00 2001
From: Weihang Lo <me@weihanglo.tw>
Date: Thu, 2 Apr 2026 23:29:46 -0400
Subject: [PATCH] fix(zlib): remove unnecessary defines

in madler/zlib@81cc0bebe, zlib started using EWOULDBLOCK,
which when `-D_POSIX_SOURCE` is set, FreeBSD would hide
`#define EWOULDBLOCK EAGAIN`.
See <https://github.com/freebsd/freebsd-src/blob/3e9f4fd6fc50300d052d5619d82a14d3488483d5/sys/sys/errno.h#L92-L93>

However,
`_POSIX_SOURCE` isn't really set in `./configure` or `CMakeLists.txt`.
We should follow whatever upstream native build does,
rather than do our own way.
Along with `_POSIX_SOURCE`,
`_C99_SOURCE` (apple), `_XOPEN_SOURCE` (solaris) are removed aslo.

This was found in

* <https://github.com/rust-lang/rust/pull/154734>
* <https://triage.rust-lang.org/gha-logs/rust-lang/rust/69786578177>

The rust-lang/rust try-build suceeded with a couple of tier 2 platforms:
<https://github.com/rust-lang/rust/pull/154734#issuecomment-4184407625>

* dist-powerpc-linux
* dist-riscv64-linux
* dist-s390x-linux
* dist-sparcv9-solaris
* dist-x86_64-apple
* dist-x86_64-illumos
* dist-x86_64-netbsd
* dist-x86_64-solaris
* x86_64-freebsd
---
 build.rs | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/build.rs b/build.rs
index 84d87f7d..4cd8291d 100644
--- a/build.rs
+++ b/build.rs
@@ -135,15 +135,8 @@ fn build_zlib(cfg: &mut cc::Build, target: &str) {
 
     if !target.contains("windows") {
         cfg.define("_LARGEFILE64_SOURCE", None);
-        cfg.define("_POSIX_SOURCE", None);
         cfg.flag("-fvisibility=hidden");
     }
-    if target.contains("apple") {
-        cfg.define("_C99_SOURCE", None);
-    }
-    if target.contains("solaris") {
-        cfg.define("_XOPEN_SOURCE", "700");
-    }
 
     cfg.compile("z");