From 4a714e100e4a39d6219181bfc412ba208c9bb31a Mon Sep 17 00:00:00 2001
From: Davide Beatrici <git@davidebeatrici.dev>
Date: Sat, 4 Jan 2025 03:54:13 +0100
Subject: [PATCH] cgen: define _GNU_SOURCE on Linux

For gettid() declaration (and other GNU-specific bits).
---
 vlib/v/gen/c/cgen.v | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index 79a6bad86a3365..d67a4c6ec1b183 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -906,6 +906,10 @@ pub fn (mut g Gen) init() {
 #endif
 ')
 		}
+		if g.pref.os == .linux {
+			// For gettid() declaration (and other GNU-specific bits).
+			g.cheaders.writeln('#define _GNU_SOURCE')
+		}
 		if g.pref.os == .wasm32 {
 			g.cheaders.writeln('#define VWASM 1')
 			// Include <stdint.h> instead of <inttypes.h> for WASM target