Unable to install under Catalina 10.15.7

[emilebosch]

Unfortunately, not able to install under ruby 2.6.6p146 (2020-03-31 revision 67876) [x86_64-darwin18] on Catalina. Any ideas?

Installing libomp:

anomaly (emile) ∆ brew install libomp
Warning: libomp 12.0.1 is already installed and up-to-date.
To reinstall 12.0.1, run:
  brew reinstall libomp

Then installing the gem:

current directory: /Users/xx/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/isotree-0.2.1/ext/isotree
/Users/xx/.rbenv/versions/2.6.6/bin/ruby -I /Users/xx/.rbenv/versions/2.6.6/lib/ruby/site_ruby/2.6.0 -r ./siteconf20210727-3435-inbz3a.rb extconf.rb
/Users/xx/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rice-4.0.2/lib/mkmf-rice.rb:16: warning: already initialized constant MakeMakefile::CONFTEST_C
/Users/xx/.rbenv/versions/2.6.6/lib/ruby/2.6.0/mkmf.rb:259: warning: previous definition of CONFTEST_C was here
checking for rice/rice.hpp in /Users/xx/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rice-4.0.2/include... yes
checking for -lc++... yes
checking for -lomp... yes
creating Makefile

current directory: /Users/xx/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/isotree-0.2.1/ext/isotree
make DESTDIR\= clean

current directory: /Users/xx/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/isotree-0.2.1/ext/isotree
make DESTDIR\=
compiling ext.cpp
clang: error: unsupported option '-fopenmp'
make: *** [ext.o] Error 1

make failed, exit code 2

[ankane]

Can you try the debug branch and share the output? https://github.com/ankane/isotree/compare/debug

gem "isotree", github: "ankane/isotree", branch: "debug", submodules: true

[ankane]

Cleaning up issues