Add missing #include for wait().


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@84207 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/CIndex/CIndex.cpp b/tools/CIndex/CIndex.cpp
index 970ba38..33099cc 100644
--- a/tools/CIndex/CIndex.cpp
+++ b/tools/CIndex/CIndex.cpp
@@ -24,6 +24,7 @@
 #include "clang/Frontend/ASTUnit.h"
 #include <cstdio>
 #include <dlfcn.h>
+#include <sys/wait.h>
 #include "llvm/System/Path.h"
 
 using namespace clang;