From 8ebfe91e44452a2f879c8f22c59b486c6b91eec9 Mon Sep 17 00:00:00 2001
From: meh <meh@schizofreni.co>
Date: Wed, 23 Dec 2015 02:34:16 +0100
Subject: [PATCH] build: default undefined var to false

---
 sys/build.rs | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/sys/build.rs b/sys/build.rs
index 65c2791..9ddadcb 100644
--- a/sys/build.rs
+++ b/sys/build.rs
@@ -227,15 +227,19 @@ fn feature(header: &str, feature: Option<&str>, var: &str) -> io::Result<()> {
 
 	try!(write!(try!(File::create(output().join("check.c"))), r#"
 		#include <stdio.h>
-		#include <{}>
+		#include <{header}>
+
+		#ifndef {var}
+		#define {var} 0
+		#endif
 
 		int
 		main (int argc, char* argv[])
 		{{
-			printf("%d\n", {});
+			printf("%d\n", {var});
 			return 0;
 		}}
-	"#, header, var));
+	"#, header=header, var=var));
 
 	if Command::new("cc").current_dir(&output())
 		.arg("-I").arg(search().join("dist").join("include").to_string_lossy().into_owned())