From 7f41ef32c8c887ee23ca83da4dfd7a4f27e01186 Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Wed, 10 Feb 2016 23:09:51 +0100
Subject: [PATCH] sysdep.h: don't assume <error.h> is available on all Linux
 platforms

The current logic in sysdep.h assumes that whenever you have __linux__
or __GLIBC__ defined, then <error.h> functionality is
available. However, the <error.h> functionality is a glibc-ism, not
available in more standard-conformant C libraries such as the musl C
library. With musl, __linux__ is defined (but of course not
__GLIBC__). With the current logic, sysdep.h assumes that <error.h> is
available, which isn't the case.

This patch therefore changes the logic to only use <error.h> when
__GLIBC__ is defined. It fixes the following build error:

In file included from tunip.c:87:0:
sysdep.h:41:19: fatal error: error.h: No such file or directory
 #include <error.h>

Original patch from
http://git.alpinelinux.org/cgit/aports/tree/testing/vpnc/working.patch.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 sysdep.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sysdep.h b/sysdep.h
index 137bf6d..fb65b31 100644
--- a/sysdep.h
+++ b/sysdep.h
@@ -38,11 +38,14 @@ int tun_get_hwaddr(int fd, char *dev, uint8_t *hwaddr);
 
 /***************************************************************************/
 #if defined(__linux__) || defined(__GLIBC__)
+
+#ifdef __GLIBC__
 #include <error.h>
+#define HAVE_ERROR     1
+#endif
 
 #define HAVE_VASPRINTF 1
 #define HAVE_ASPRINTF  1
-#define HAVE_ERROR     1
 #define HAVE_UNSETENV  1
 #define HAVE_SETENV    1
 #endif
-- 
2.6.4