Fix -iconv/-no-iconv switch

[titobrasolin]

See comment:
e529dc6#r26652161

[mirko]

Apparently -iconv requires ICU as a dependency so this change caused a regression. Can you confirm / fix this?

[titobrasolin]

@mirko Sorry for the regression, maybe I can fix it but it will not happen before two or three days (at the moment I do not have access to my tools). I apologize very much for the inconvenience

[titobrasolin]

Hello @mirko I couldn't fix the issue, the error is: "Feature 'iconv' was enabled, but the pre-condition '!features.icu && (features.posix-libiconv || features.sun-libiconv || features.gnu-libiconv)' failed."

The pre-condition is defined here: https://github.com/qt/qtbase/blob/v5.9.1/src/corelib/configure.json#L245

As far as I understand -iconv doesn't require ICU as a dependency, it shouldn't even be possible to configure Qt to use both iconv and ICU: http://lists.qt-project.org/pipermail/development/2017-January/028392.html

I will investigate more thoroughly, but for now it is better to restore line 363 from

$(if $(CONFIG_BUILD_NLS),-iconv,-no-iconv) \

to

$(if $(CONFIG_BUILD_NLS),-no-iconv,-no-iconv) \

Now I'm creating a pull request to revert the changes.