Always include <sys/cdefs.h> first.

Otherwise you can't be sure that things like __BIONIC__ work.

Change-Id: Ic5e59988b69419828c3b1a97332c7e2ab58e09a1
diff --git a/libc/include/android/crash_detail.h b/libc/include/android/crash_detail.h
index 946a3ab..490ec8c 100644
--- a/libc/include/android/crash_detail.h
+++ b/libc/include/android/crash_detail.h
@@ -33,9 +33,10 @@
  * @brief Attach extra information to android crashes.
  */
 
-#include <stddef.h>
 #include <sys/cdefs.h>
 
+#include <stddef.h>
+
 __BEGIN_DECLS
 
 typedef struct crash_detail_t crash_detail_t;