Add a dllimport test.

Thanks to rnk for the suggestion.

llvm-svn: 328800

clang/test/CodeGen/flip-dllimport.c

@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -triple x86_64-windows-msvc -fms-extensions -emit-llvm -o - %s | FileCheck %s
+
+__declspec(dllimport) void f();
+void g() { f(); } // use it
+
+// CHECK: define dso_local dllexport void @f
+void f() { }