fix(zlib): define _POSIX_C_SOURCE=200112L

weihanglo · weihanglo · commit 73817ec334e2 · 2026-04-02T23:42:10.000-04:00
This follows upstream's change in madler/zlib@1382e6611 due to EWOULDBLOCK is used since madler/zlib@81cc0bebe and `-D_POSIX_SOURCE` would hide `#define EWOULDBLOCK EAGAIN`. See <https://github.com/freebsd/freebsd-src/blob/3e9f4fd6fc50300d052d5619d82a14d3488483d5/sys/sys/errno.h#L92-L93> Actually I feel like _POSIX_C_SOURCE=200112L maybe redundant though let's just do whatever upstream does This was found in * <rust-lang/rust#154734> * <https://triage.rust-lang.org/gha-logs/rust-lang/rust/69786578177>
diff --git a/build.rs b/build.rs
@@ -135,7 +135,7 @@ fn build_zlib(cfg: &mut cc::Build, target: &str) {
 
     if !target.contains("windows") {
         cfg.define("_LARGEFILE64_SOURCE", None);
-        cfg.define("_POSIX_SOURCE", None);
+        cfg.define("_POSIX_C_SOURCE", "200112L");
         cfg.flag("-fvisibility=hidden");
     }
     if target.contains("apple") {

Original file line number	Diff line number	Diff line change
`@@ -135,7 +135,7 @@ fn build_zlib(cfg: &mut cc::Build, target: &str) {`
`135`	`135`
`136`	`136`	`if !target.contains("windows") {`
`137`	`137`	`cfg.define("_LARGEFILE64_SOURCE", None);`
`138`		`- cfg.define("_POSIX_SOURCE", None);`
	`138`	`+ cfg.define("_POSIX_C_SOURCE", "200112L");`
`139`	`139`	`cfg.flag("-fvisibility=hidden");`
`140`	`140`	`}`
`141`	`141`	`if target.contains("apple") {`