Merge pull request #4470 from d3zd3z/fix-posix-define
Check if feature macro is defined before define it
diff --git a/ChangeLog.d/posix-define.txt b/ChangeLog.d/posix-define.txt
new file mode 100644
index 0000000..98cf2d0
--- /dev/null
+++ b/ChangeLog.d/posix-define.txt
@@ -0,0 +1,6 @@
+Bugfix
+ * In library/net_sockets.c, _POSIX_C_SOURCE and _XOPEN_SOURCE are
+ defined to specific values. If the code is used in a context
+ where these are already defined, this can result in a compilation
+ error. Instead, assume that if they are defined, the values will
+ be adequate to build Mbed TLS.
diff --git a/library/net_sockets.c b/library/net_sockets.c
index ad1ac13..8f79b74 100644
--- a/library/net_sockets.c
+++ b/library/net_sockets.c
@@ -20,8 +20,12 @@
/* Enable definition of getaddrinfo() even when compiling with -std=c99. Must
* be set before config.h, which pulls in glibc's features.h indirectly.
* Harmless on other platforms. */
+#ifndef _POSIX_C_SOURCE
#define _POSIX_C_SOURCE 200112L
+#endif
+#ifndef _XOPEN_SOURCE
#define _XOPEN_SOURCE 600 /* sockaddr_storage */
+#endif
#include "common.h"
