headers: Remove RtlUnwind from winternl.h

Function RtlUnwind is already declared in the winnt.h header file.
And winternl.h includes windef.h which includes winnt.h.

Moreover declaration of RtlUnwind in winternl.h is incompatible with
the declaration in winnt.h and causes compile warning:

/usr/local/include/winternl.h:1130:14: warning: ‘RtlUnwind’ redeclared without dllimport attribute: previous dllimport ignored [-Wattributes]
   VOID NTAPI RtlUnwind (PVOID TargetFrame,PVOID TargetIp,PEXCEPTION_RECORD ExceptionRecord,PVOID ReturnValue);
              ^~~~~~~~~

Signed-off-by: LIU Hao <lh_mouse@126.com>

mingw-w64-headers/include/winternl.h

diff --git a/mingw-w64-headers/include/winternl.h b/mingw-w64-headers/include/winternl.h
index 95422dc..1486686 100644
--- a/mingw-w64-headers/include/winternl.h
+++ b/mingw-w64-headers/include/winternl.h
@@ -1127,7 +1127,6 @@
   NTSTATUS NTAPI RtlCharToInteger (PCSZ String,ULONG Base,PULONG Value);
   NTSTATUS NTAPI RtlConvertSidToUnicodeString(PUNICODE_STRING UnicodeString,PSID Sid,BOOLEAN AllocateDestinationString);
   ULONG NTAPI RtlUniform(PULONG Seed);
-  VOID NTAPI RtlUnwind (PVOID TargetFrame,PVOID TargetIp,PEXCEPTION_RECORD ExceptionRecord,PVOID ReturnValue);
   BOOL NTAPI RtlDosPathNameToNtPathName_U(PCWSTR DosPathName, PUNICODE_STRING NtPathName, PCWSTR *NtFileNamePart, VOID *DirectoryInfo);
   BOOLEAN NTAPI RtlPrefixUnicodeString(PCUNICODE_STRING String1, PCUNICODE_STRING String2, BOOLEAN CaseInSensitive);
   BOOLEAN NTAPI RtlCreateUnicodeStringFromAsciiz(PUNICODE_STRING target, LPCSTR src);