Add missing header guards.

llvm-svn: 317267
diff --git a/llvm/include/llvm-c/DebugInfo.h b/llvm/include/llvm-c/DebugInfo.h
index 15f6b57..2c2fdbd 100644
--- a/llvm/include/llvm-c/DebugInfo.h
+++ b/llvm/include/llvm-c/DebugInfo.h
@@ -14,6 +14,9 @@
 ///
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_C_DEBUGINFO_H
+#define LLVM_C_DEBUGINFO_H
+
 #include "llvm-c/Core.h"
 
 #ifdef __cplusplus
@@ -200,3 +203,5 @@
 #ifdef __cplusplus
 } // end extern "C"
 #endif
+
+#endif