Declare RtlGUIDFromString and RtlStringFromGUID.

diff --git a/include/winternl.h b/include/winternl.h
index 0ad27d1..67be34a 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -1919,6 +1919,7 @@
 ULONG     WINAPI RtlGetProcessHeaps(ULONG,HANDLE*);
 NTSTATUS  WINAPI RtlGetSaclSecurityDescriptor(PSECURITY_DESCRIPTOR,PBOOLEAN,PACL *,PBOOLEAN);
 NTSTATUS  WINAPI RtlGetVersion(RTL_OSVERSIONINFOEXW*);
+NTSTATUS  WINAPI RtlGUIDFromString(PUNICODE_STRING,GUID*);
 
 PSID_IDENTIFIER_AUTHORITY WINAPI RtlIdentifierAuthoritySid(PSID);
 PVOID     WINAPI RtlImageDirectoryEntryToData(HMODULE,BOOL,WORD,ULONG *);
@@ -2016,6 +2017,7 @@
 NTSTATUS  WINAPI RtlSetSaclSecurityDescriptor(PSECURITY_DESCRIPTOR,BOOLEAN,PACL,BOOLEAN);
 NTSTATUS  WINAPI RtlSetTimeZoneInformation(const RTL_TIME_ZONE_INFORMATION*);
 ULONG     WINAPI RtlSizeHeap(HANDLE,ULONG,PVOID);
+NTSTATUS  WINAPI RtlStringFromGUID(REFGUID,PUNICODE_STRING);
 LPDWORD   WINAPI RtlSubAuthoritySid(PSID,DWORD);
 LPBYTE    WINAPI RtlSubAuthorityCountSid(PSID);
 NTSTATUS  WINAPI RtlSystemTimeToLocalTime(const LARGE_INTEGER*,PLARGE_INTEGER);