Installing clang from sources broke everything

  apt, c++, clang, ubuntu

I have downloaded and compiled the clang library from sources. They have many additional packages, so build them all (including libc++, openmp etc). I wanted to install it in /opt so I could share it with some other people using the machine. But instead of passing the install dir to cmake using the CMAKE_INSTALL_PREFIX, I did sudo make DESTDIR=/opt/clang install
This messed up the entire machine. When I try to do apt --fix-broken install --dry-run I get this:

The following packages will be REMOVED:
0 upgraded, 0 newly installed, 1 to remove and 7 not upgraded.
1 not fully installed or removed.
Remv libc++1 [6.0-2]

And it is not only the libc++ that has problems. I had several clang compilers installed with the package manager, and they are all failing.
I have dry-running few commands, but it shows a lot of unmet dependencies and other problematic output :).

Where should I star to recover the machine?


p.s. I know that there are "several stack overflow", so this one might not be the one asking these kind of questions. If so please point me to the good one.

Source: Windows Questions C++