Guard the _GNU_SOURCE #define.
It is hard to control what flags consumers may try to build us with.
Account for someone adding _GNU_SOURCE to the build line.
Change-Id: I4c931da70a9dccc89382ce9100c228c29d28d4bf
Reviewed-on: https://boringssl-review.googlesource.com/13621
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
(cherry picked from commit e025f3050761b0f737a3f7b53e6a56b07f7bcb9a)
diff --git a/crypto/rand/urandom.c b/crypto/rand/urandom.c
index 2572625..f0f31f2 100644
--- a/crypto/rand/urandom.c
+++ b/crypto/rand/urandom.c
@@ -12,7 +12,9 @@
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+#if !defined(_GNU_SOURCE)
#define _GNU_SOURCE /* needed for syscall() on Linux. */
+#endif
#include <openssl/rand.h>
