implement the microsoft/gnu "__COUNTER__" macro: rdar://4329310


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68933 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/PCH/variables.h b/test/PCH/variables.h
index 7b27671..82e87aa 100644
--- a/test/PCH/variables.h
+++ b/test/PCH/variables.h
@@ -16,3 +16,11 @@
 
 #define A_MACRO_IN_THE_PCH 492
 #define FUNCLIKE_MACRO(X, Y) X ## Y
+
+#define PASTE2(x,y) x##y
+#define PASTE1(x,y) PASTE2(x,y)
+#define UNIQUE(x) PASTE1(x,__COUNTER__)
+
+int UNIQUE(a);  // a0
+int UNIQUE(a);  // a1
+