Qt 5 RC1 build fails under windows with -iconv

I've downloaded Qt5 RC1 from downloads page and run
configure.bat -debug-and-release -opensource -iconv
Then I run nmake to build Qt5. But build fails:

codecs\qtextcodec.cpp(288) : error C2061: syntax error : identifier 'QIconvCodec'

The reason is in line 58 of qiconvcodec_p.h:

#if defined(Q_OS_UNIX) && !defined(QT_NO_ICONV) && !defined(QT_BOOTSTRAPPED)

My OS Windows is excluded by this directive.
When I run configure.bat -help I see "+" sign near iconv options:

 +  -iconv ............. Enable support for iconv(3).
 +  -sun-iconv ......... Enable support for iconv(3) using sun-iconv.
 +  -gnu-iconv ......... Enable support for iconv(3) using gnu-libiconv.

Does it mean that iconv is enabled on my platform?
I think you need either change configure script to disable iconv under windows or change qiconvcodec_p.h to build under windows.

See logs attached.