Unable to install both amd64 and i386 version of libc++1-7

[Bas Vermeulen]

I have a private debian package that needs both amd64 and i386 version of libc++1-7.
When I install it, the amd64 version gets installed first, and the i386 version fails to install because it tries to overwrite files from the amd64 version.

This work(s/ed) for libc++1_6.0-2, where both versions can be installed at the same time.

sudo apt install libc++1-7 libc++1-7:i386
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  libc++abi1-7 libc++abi1-7:i386
Suggested packages:
  clang clang:i386
The following packages will be REMOVED:
  libc++1 libc++1:i386 libc++abi1 libc++abi1:i386
The following NEW packages will be installed:
  libc++1-7 libc++1-7:i386 libc++abi1-7 libc++abi1-7:i386
0 upgraded, 4 newly installed, 4 to remove and 0 not upgraded.
Need to get 0 B/516 kB of archives.
After this operation, 176 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
dpkg: libc++1:i386: dependency problems, but removing anyway as you requested:
 tobyl4-image-tools depends on libc++1:i386.
 tobyl4-image-tools depends on libc++1:i386.

(Reading database ... 401718 files and directories currently installed.)
Removing libc++1:i386 (6.0-2) ...
dpkg: libc++1:amd64: dependency problems, but removing anyway as you requested:
 tobyl4-image-tools depends on libc++1.
 tobyl4-image-tools depends on libc++1.

Removing libc++1:amd64 (6.0-2) ...
(Reading database ... 401710 files and directories currently installed.)
Preparing to unpack .../libc++1-7_1%3a7-3~ubuntu0.18.04.1_i386.deb ...
Unpacking libc++1-7:i386 (1:7-3~ubuntu0.18.04.1) ...
Selecting previously unselected package libc++1-7:amd64.
Preparing to unpack .../libc++1-7_1%3a7-3~ubuntu0.18.04.1_amd64.deb ...
Unpacking libc++1-7:amd64 (1:7-3~ubuntu0.18.04.1) ...
dpkg: error processing archive /var/cache/apt/archives/libc++1-7_1%3a7-3~ubuntu0.18.04.1_amd64.deb (--unpack):
 trying to overwrite shared '/usr/lib/llvm-7/lib/libc++.so.1.0', which is different from other instances of package libc++1-7:amd64
Errors were encountered while processing:
 /var/cache/apt/archives/libc++1-7_1%3a7-3~ubuntu0.18.04.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)