Use extern C guards in all headers

The project uses a mix of C and C++ requiring
extern "C" guards from C++ code both within the
project & from C++ apps that use libcper. That
won't be required with this change.

Change-Id: I835dd05166732ca213c72eae2904815a8769599b
Signed-off-by: Karthik Rajagopalan <krajagopalan@nvidia.com>
diff --git a/edk/Cper.h b/edk/Cper.h
index 5fd5b48..f1bbdb1 100644
--- a/edk/Cper.h
+++ b/edk/Cper.h
@@ -9,11 +9,16 @@
   GUIDs defined in UEFI 2.7 Specification.

 

 **/
-#include "BaseTypes.h"
 
 #ifndef __CPER_GUID_H__
 #define __CPER_GUID_H__
 
+#include "BaseTypes.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #pragma pack(push, 1)
 
 #define EFI_ERROR_RECORD_SIGNATURE_START SIGNATURE_32('C', 'P', 'E', 'R')
@@ -1400,4 +1405,8 @@
 extern EFI_GUID gEfiNvidiaErrorSectionGuid;
 #pragma pack(pop)
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif