Add get_architectures() and C++ versions

* get_architectures() returns the primary and the secondary
  architectures in one array. That turned out to be convenient.
* Add C++ versions for get[_secondary]_architectures(), returning a
  BStringList.

headers/os/support/Architecture.h

@@ -18,10 +18,25 @@ const char*	get_architecture();
 const char*	get_primary_architecture();
 size_t		get_secondary_architectures(const char** architectures,
 				size_t count);
+size_t		get_architectures(const char** architectures, size_t count);
 const char*	guess_architecture_for_path(const char* path);
 
 
 __END_DECLS
 
 
+/* C++ API */
+#ifdef __cplusplus
+
+
+#include <StringList.h>
+
+
+status_t	get_secondary_architectures(BStringList& _architectures);
+status_t	get_architectures(BStringList& _architectures);
+
+
+#endif
+
+
 #endif	/* _SUPPORT_ARCHITECTURE_H */

headers/private/system/architecture_private.h

@@ -16,6 +16,7 @@ const char*	__get_architecture();
 const char*	__get_primary_architecture();
 size_t		__get_secondary_architectures(const char** architectures,
 				size_t count);
+size_t		__get_architectures(const char** architectures, size_t count);
 const char*	__guess_architecture_for_path(const char* path);