Installation fails on jRuby

[Izzy]

When trying to install I get:
checking for sqlite3ext.h... RuntimeError: The compiler failed to generate an executable file. You have to install development tools first.

I'm running MacOS 10.15.5, with libpng, libjpeg & imagemagick installed.
Installation on "plain" ruby (2.6.0 that comes bundled with Xcode) works like a charm.

My gem env:

RubyGems Environment:
  - RUBYGEMS VERSION: 3.0.2
  - RUBY VERSION: 2.5.3 (2019-08-12 patchlevel 0) [java]
  - INSTALLATION DIRECTORY: /Users/<user>/.gem/jruby/2.5.3
  - USER INSTALLATION DIRECTORY: /Users/<user>/.gem/jruby/2.5.0
  - RUBY EXECUTABLE: /opt/rubies/jruby-9.2.8.0/bin/jruby
  - GIT EXECUTABLE: /nix/var/nix/gcroots/dev-profiles/user-extra-profile/bin/git
  - EXECUTABLE DIRECTORY: /Users/<user>/.gem/jruby/2.5.3/bin
  - SPEC CACHE DIRECTORY: /Users/<user>/.gem/specs
  - SYSTEM CONFIGURATION DIRECTORY: /opt/rubies/jruby-9.2.8.0/etc
  - RUBYGEMS PLATFORMS:
    - ruby
    - universal-java-1.8
  - GEM PATHS:
     - /Users/<user>/.gem/jruby/2.5.3
     - /opt/rubies/jruby-9.2.8.0/lib/ruby/gems/2.5.0
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
     - "install" => "--no-rdoc --no-ri --env-shebang"
     - "update" => "--no-rdoc --no-ri --env-shebang"
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /Users/<user>/.gem/jruby/2.5.3/bin
     - /opt/rubies/jruby-9.2.8.0/lib/ruby/gems/2.5.0/bin
     - /opt/rubies/jruby-9.2.8.0/bin
     - /Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home/bin
     - /usr/local/sbin
     - /usr/local/opt/sqlite/bin
     - /Users/<user>/.nix-profile/bin
     - /opt/dev/bin/user
     - /Users/<user>/.nix-profile/bin
     - /nix/var/nix/gcroots/dev-profiles/user-extra-profile/bin
     - /Users/<user>/.pyenv/shims
     - /usr/local/bin
     - /usr/bin
     - /bin
     - /usr/sbin
     - /sbin
     - /Library/TeX/texbin
     - /opt/X11/bin
     - /Library/Apple/usr/bin

I tried adding the path to sqlite3ext.h to the package installation options via bundle
bundle config --local build.phashion "--with-cppflags=-I/usr/local/opt/sqlite/include"
But with no success