Error in Building qtwebengine in Qt 5.12.4 on msvc2017 with proprietary codecs

 
I want to build Qt 5.12.4 on Windows 10 to have qtwebengine with proprietary codec for x86 applications but I get the `64-bit cross-building or native toolchain is required` error by running the following command.

qmake .\qtwebengine – -webengine-proprietary-codecs

 Before running qmake command, I do the following steps:

1. Run Windows command prompt as Administrator. change directory to

C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\VC\Auxiliary\Build

and run the following script:

 

vcvarsall.bat amd64_x86

 

I run this command because I want to build Qt WebEngine for x86 applications base on the [Qt document.|https://doc.qt.io/qt-5/qtwebengine-platform-notes.html]

1. Change directory to

D:\Qt\Qt5.12.4\5.12.4\Src

and run the below command:

configure -webengine-proprietary-codecs

After this configuration setting, I got this result:

 I installed these Qt webengine compile prerequisites:

-Python 2.7.15

-Bison, Flex from here

-GPerf(32bit) from here

-ActivePerl(64bit) from here

-LLVM(64bit) from here

-Visual Studio 2017

-Windows 10 SDK

I also add them to Windows path and restart my machine.

Besides, I also install MSVC 2015 64-bit, MSVC 2017 32-bit, MSVC 2017 64-bit, Sources, Qt WebEngine, and Qt Network Authorization components.

---------------------------UPDATE ON 2019-07-09 --------------------------
I found this bug source and mention the solution in the following comment.
#https://bugreports.qt.io/browse/QTBUG-76951?focusedCommentId=468052&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-468052
Now the following error exist when I ran `nmake`.
`fatal error U1073: don't know how to make 'D:\Qt\Qt5.12.4\5.12.4\Src\qtbase\lib\Qt5Gui.lib' `