Is it possible to provide libc6 to prevent conflicts?

[CalcProgrammer1]

If you try to add i386 or amd64 architecture and install any i386 or amd64 app, Debian will try to install libc6 for that architecture and will error out as a file conflict with the library provided with box86/box64 occurs. Is it possible to mark these packages as provides libc6:i386/amd64?

[rpm-arch]

+1

This causes conflict with steamcmd official deb. Here is an example starting with Bookworm on Ampere Altra CPU (Aarch64)

# Install box86
dpkg --add-architecture armhf
apt update
apt install -y wget gpg
wget https://ryanfortner.github.io/box86-debs/box86.list -O /etc/apt/sources.list.d/box86.list
wget -qO- https://ryanfortner.github.io/box86-debs/KEY.gpg | gpg --dearmor -o /etc/apt/trusted.gpg.d/box86-debs-archive-keyring.gpg
apt update
apt install -y box86-generic-arm

# Install steamcmd
dpkg --add-architecture i386
sed -i 's/^Components: main$/& contrib non-free non-free-firmware/' /etc/apt/sources.list.d/debian.sources
apt update
apt install -y steamcmd

Result:

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
steamcmd:i386 is already the newest version (0~20180105-5).
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 steamcmd:i386 : Depends: libstdc++6:i386 but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).

apt --fix-broken install
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Correcting dependencies... Done
The following additional packages will be installed:
  libstdc++6:i386
The following NEW packages will be installed:
  libstdc++6:i386
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
6 not fully installed or removed.
Need to get 661 kB of archives.
After this operation, 2771 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://deb.debian.org/debian stable/main i386 libstdc++6 i386 12.2.0-14 [661 kB]
Fetched 661 kB in 0s (6107 kB/s)    
debconf: delaying package configuration, since apt-utils is not installed
(Reading database ... 7364 files and directories currently installed.)
Preparing to unpack .../libstdc++6_12.2.0-14_i386.deb ...
Unpacking libstdc++6:i386 (12.2.0-14) ...
dpkg: error processing archive /var/cache/apt/archives/libstdc++6_12.2.0-14_i386.deb (--unpack):
 trying to overwrite '/usr/lib/i386-linux-gnu/libstdc++.so.6', which is also in package box86-generic-arm:armhf 0.3.7+20240918.54c806c-1
Errors were encountered while processing:
 /var/cache/apt/archives/libstdc++6_12.2.0-14_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Similar error occurs in reverse, if install steamcmd or libstdc++6:i386 before box86:

dpkg: error processing archive /var/cache/apt/archives/box86-generic-arm_0.3.7+20240918.54c806c-1_armhf.deb (--unpack):
 trying to overwrite '/usr/lib/i386-linux-gnu/libstdc++.so.6', which is also in package libstdc++6:i386 12.2.0-14

There is workaround by downloading deb and forcing overwrite, if steamcmd is installed first:

apt download box86-generic-arm
dpkg -i --force-overwrite box86*.deb