Xing Xue:  port to IBM XLC++/AIX.

llvm-svn: 188396
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 5d1a701d6def1e4e6ae3d5bce67efd40b07fba16
diff --git a/src/thread.cpp b/src/thread.cpp
index 1fd8bb0..cdfa2fd 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -14,9 +14,9 @@
 #include "limits"
 #include <sys/types.h>
 #if !defined(_WIN32)
-#if !defined(__sun__) && !defined(__linux__)
+#if !defined(__sun__) && !defined(__linux__) && !defined(_AIX)
 #include <sys/sysctl.h>
-#endif // !__sun__ && !__linux__
+#endif // !__sun__ && !__linux__ && !_AIX
 #include <unistd.h>
 #endif // !_WIN32