I managed to get things working. The problem indeed seemed to be default channel vs conda-forge. I mispoke earlier. Only package names cxx-compiler and compilers were comming from conda-forge. The gcc_linux-64 package was from the default channel.
The following lines in my .condarc seem to be the culprit. Removing them causes gcc_linux-64 to come from conda-forge and my root application to compile.
channels:
- defaults
- conda-forge
Thank you very much for all the help!
–
Karol Krizka