llvm/test/TableGen/duplicate-include.inc - llvm-project - Git at Google

 #ifndef DUPLICATE_INCLUDE
 #define DUPLICATE_INCLUDE

 // This is used by the duplicate-include.td test
 def InInclude;

 #endif
	#ifndef DUPLICATE_INCLUDE
	#define DUPLICATE_INCLUDE

	// This is used by the duplicate-include.td test
	def InInclude;

	#endif