Add gcc macro to remove pack() for gcc build

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@1962 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Include/Common/BootScript.h

@@ -40,7 +40,9 @@
 #define EFI_BOOT_SCRIPT_TABLE_OPCODE                  0xAA
 #define EFI_BOOT_SCRIPT_TERMINATE_OPCODE              0xFF
 
+#ifndef __GNUC__
 #pragma pack(1)
+#endif
 
 //
 // EFI Boot Script Width
@@ -206,6 +208,8 @@ typedef union {
   UINT8                                 *Raw;
 } BOOT_SCRIPT_POINTERS;
 
+#ifndef __GNUC__
 #pragma pack()
+#endif
 
 #endif