Say you do:
gem install ruby-debug
Error installing ruby-debug.
ERROR: Failed to build gem native extension.
Can’t handle 1.9.x yet
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Here’s one solution:
1. make sure you reference the right ruby headers, e.g.
gem install ruby-debug19 — -with-ruby-include=$rvm_path/src/ruby-head/
(make sure you get the right number of hyphens!)