Fix conversion warning in isql

Author: mrotteveel

src/isql/isql.epp

@@ -344,7 +344,7 @@ static int win32ReadConsole(FILE* file, CharBuffer& mbBuffer)
 	// buffers and set ERROR_NOT_ENOUGH_MEMORY error. Thus, use initial buffer size
 	// twice less than for Windows 10 and handle error by reducing the buffer size.
 
-	static size_t maxLineLength = IsWindows10OrGreater() ? MAX_USHORT : MAX_SSHORT;
+	static DWORD maxLineLength = IsWindows10OrGreater() ? MAX_USHORT : MAX_SSHORT;
 	WCHAR* wideBuf = wideBuffer->getBuffer(maxLineLength, false);
 
 	DWORD charsRead;