Add shlwapi.wvnsprintf[AW], header info and comments.

dlls/shlwapi/shlwapi.spec

@@ -687,8 +687,10 @@ debug_channels (shell)
 @ stub    UrlIsW
 @ stdcall UrlUnescapeA(str ptr ptr long) UrlUnescapeA
 @ stdcall UrlUnescapeW(wstr ptr ptr long) UrlUnescapeW
-@ varargs wnsprintfA(ptr long str)wnsprintfA
-@ varargs wnsprintfW(ptr long wstr)wnsprintfW
+@ varargs wnsprintfA(ptr long str) wnsprintfA
+@ varargs wnsprintfW(ptr long wstr) wnsprintfW
+@ forward wvnsprintfA user32.wvsnprintfA
+@ forward wvnsprintfW user32.wvsnprintfW
 
 
 # exported in later versions

include/shlwapi.h

@@ -199,6 +199,13 @@ LPSTR WINAPI StrFormatByteSizeA ( DWORD dw, LPSTR pszBuf, UINT cchBuf );
 LPWSTR WINAPI StrFormatByteSizeW ( DWORD dw, LPWSTR pszBuf, UINT cchBuf );
 #define StrFormatByteSize WINELIB_NAME_AW(StrFormatByteSize)
 
+INT WINAPI wvnsprintfA(LPSTR lpOut, INT cchLimitIn, LPCSTR lpFmt, va_list arglist);
+INT WINAPI wvnsprintfW(LPWSTR lpOut, INT cchLimitIn, LPCWSTR lpFmt, va_list arglist);
+#define wvnsprintf WINELIB_NAME_AW(wvnsprintf)
+
+INT WINAPIV wnsprintfA(LPSTR lpOut, INT cchLimitIn, LPCSTR lpFmt, ...);
+INT WINAPIV wnsprintfW(LPWSTR lpOut, INT cchLimitIn, LPCWSTR lpFmt, ...);
+#define wnsprintf WINELIB_NAME_AW(wnsprintf)
 
 
 struct _STRRET;