Packed unaligned_type

This way, unaligned_types like etl::be_uint32_t can be used in places where POD types are expected.

Author: rolandreichweinbmw

include/etl/platform.h

@@ -454,6 +454,14 @@ SOFTWARE.
   #define ETL_HAS_INITIALIZER_LIST 0
 #endif
 
+//*************************************
+// Determine if the ETL should use __attribute__((packed).
+#if defined(ETL_COMPILER_CLANG) || defined(ETL_COMPILER_GCC) || defined(ETL_COMPILER_INTEL)
+  #define ETL_PACKED __attribute__((packed))
+#else
+  #define ETL_PACKED
+#endif
+
 //*************************************
 // Check for availability of certain builtins
 #include "profiles/determine_builtin_support.h"

include/etl/unaligned_type.h

@@ -227,7 +227,7 @@ namespace etl
   ///\tparam Endian The endianness of the arithmetic type.
   //*************************************************************************
   template <typename T, int Endian_>
-  class unaligned_type : public private_unaligned_type::unaligned_type_common<sizeof(T)>
+  class ETL_PACKED unaligned_type : public private_unaligned_type::unaligned_type_common<sizeof(T)>
   {
   public: