Unsolved Error building cross-platform Qt

[bsdillon]

I have always built Qt on linux for linux, so this is my first time configuring for cross platform. I am on Ubuntu and building for windows. I followed instructions from several sites. This one (https://uncannier.com/cross-compile-qt-mingw-windows-applications-on-a-linux-host/) was the most explicit. I followed the directions but I am getting an error that appears to have nothing to do with cross platform.

Let me start by saying what I have tried. I started with a Linux-to-Linux build of a simple GUI. I copied the .pro and renamed it to program_win. I downloaded and installed g++=minwg-w64 and tried to change the kit. I got an error indicating that compiler could not produce code for that version of qmake. After some googling I installed the Qt source code and went to /Qt/5.15.0/Src/ and ran configure. As far as I can tell it ran without error, but when I ran make I get an unexpected error.

Project ERROR: Could not find feature c++2a

I'm not sure what is causing the error. I believe that I am really close to getting the cross compilation process working, but this is a blocker for me.

How do I fix the error?

[mrjj]

Hi
Im one of the naysayers he mentions in the article :)
But i was wondering if it just needs
something like
CONFIG += c++2a
or
QMAKE_CXXFLAGS += -std=c++2a

The error sounds like it wants c++20 draft enabled.