sycall: WCOREDUMP macro is not defined on AIX

Issue golang/go#19200

Change-Id: Icbbcb53aa2a34aba52a1132b486e805551f1e25e
Reviewed-on: https://go-review.googlesource.com/38363
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/libgo/go/syscall/wait.c b/libgo/go/syscall/wait.c
index 8c3b53f..a50f7d6 100644
--- a/libgo/go/syscall/wait.c
+++ b/libgo/go/syscall/wait.c
@@ -12,6 +12,10 @@
 
 #include "runtime.h"
 
+#ifndef WCOREDUMP
+#define WCOREDUMP(status) (((status) & 0200) != 0)
+#endif
+
 extern _Bool Exited (uint32_t *w)
   __asm__ (GOSYM_PREFIX "syscall.Exited.N18_syscall.WaitStatus");