* Makefile.in (DLL_IMPORTS): Drop advapi32.dll.

* autoload.cc: Enable autoloading advapi32 functions.
	* environ.cc (regopt): Use wide char arguments in reg_key functions.
	* fhandler_console.cc (beep): Ditto.  Use WCHAR throughout.
	* registry.cc (reg_key): Rewrite reg_key class to use native NT registry
	functions.  Use WCHAR string parameters throughout.  Use PCWSTR rather
	than const WCHAR.  Drop multibyte char functionality.  Drop unused
	methods.
	(get_registry_hive_path): Use RtlQueryRegistryValues to fetch path from
	registry.
	(load_registry_hive): Drop useless check for user hive being available.
	Load hive using NtLoadKey.
	* registry.h: Accommodate above changes.
	* sched.cc (sched_rr_get_interval): Use wide char arguments in reg_key
	functions.
	* shared.cc (init_installation_root): Ditto.
	(shared_info::init_obcaseinsensitive): Use RtlQueryRegistryValues to
	fetch obcaseinsensitive value.
	(shared_info::heap_slop_size): Use wide char arguments in reg_key
	functions.
	(shared_info::heap_chunk_size): Ditto.
	* syscalls.cc (gethostid): Ditto.
	* winsup.h (__WIDE): Define.
	(_WIDE): Define.
	* libc/minires-os-if.c (get_registry_dns_items): Don't fetch values
	from registry.  Just extract them from given UNICODE_STRING parameter.
	(get_registry_dns): Fetch all registry values at once using
	RtlQueryRegistryValues.

winsup/cygwin/winsup.h

@@ -70,6 +70,12 @@ int fcntl64 (int fd, int cmd, ...);
    application provided path strings we handle. */
 #define NT_MAX_PATH 32768
 
+/* This definition allows to define wide char strings using macros as
+   parameters.  See the definition of __CONCAT in newlib's sys/cdefs.h
+   and accompanying comment. */
+#define __WIDE(a) L ## a
+#define _WIDE(a) __WIDE(a)
+
 #ifdef __cplusplus
 
 extern const char case_folded_lower[];