Comment 6 for bug 1875641

No there was nothing missing. Distro 20.04 has installed all :i386 libs needed for the wine32- and wine64-bridges. Also I've set the "dpkg --add-architecture i386" befor and installed the "build-essential".

I installed the Bridges with:

apt-get install carla-bridge-wine32 carla-bridge-wine64

Weeks ago I had installed a "Ubuntu Studio 20.04 beta" and did not have these problems. Maybe that helps.

Know I solved this problems with recompiling the carla-bridge-wine32 and carla-bridge-wine64 by
installing the carla build dependencies with:

apt-get build-dep carla

Then I removed all distro packages from wine-development* (5.5)
and installed version 5.7~focal form WineHQ:

wine-devel
wine-devel-dev
wine-devel-amd64
wine-devel-i386:i386

and compiled without any error:

make win32 CC=i686-w64-mingw32-gcc CXX=i686-w64-mingw32-g++
make win64 CC=x86_64-w64-mingw32-gcc CXX=x86_64-w64-mingw32-g++

make wine32 && make wine64

Did you have the Harrison AVA-legacy-EQ (Win VST3/32)? There you can see the analyser is missing in the top. The Knobs are visible in the lower part of the plugin. (OpenGL overlay?) The older Version of Limiter No.6 (Win VST2/32) shows only a black screen. (Not the known BUG with Limiter No.6. I have the working Version)

Aamazingly, carla now also works from distro 20.04 including the both 32/64 wine-bridge together with the new packages from "WineHQ Wine-Devel 5.7~focal" installed.

It looks like the "wine-development" packages have changed since beta?!?