Targets.cpp: [cygwin] Add the predefined macro "_X86_", according to newer version of cygwin/w32api.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170188 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 5031039..96cc1cf 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -2763,6 +2763,7 @@
   virtual void getTargetDefines(const LangOptions &Opts,
                                 MacroBuilder &Builder) const {
     X86_32TargetInfo::getTargetDefines(Opts, Builder);
+    Builder.defineMacro("_X86_");
     Builder.defineMacro("__CYGWIN__");
     Builder.defineMacro("__CYGWIN32__");
     DefineStd(Builder, "unix", Opts);