Don't assume shared library is installed relative to files in lib

isolated/README.md

@@ -58,9 +58,14 @@ gcc -shared -L/path/to/ruby/lib -lruby -lc -lm isolated.o -o isolated.so
 That final shared library, `isolated.so`, is loaded like any other Ruby file, via `require` in `lib/rcee/isolated.rb`:
 
 ``` ruby
-require_relative "isolated/isolated"
+require "rcee/isolated/isolated"
 ```
 
+Even though RubyGems currently installs shared libraries relatively to Ruby
+files in lib/, it may stop doing so in the future, so it's safer to not load
+shared libraries from Ruby code using `require_relative`, but rather rely on the
+`$LOAD_PATH` and use `require`.
+
 ## Testing
 
 See [.github/workflows/isolated.yml](../.github/workflows/isolated.yml)

isolated/lib/rcee/isolated.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require_relative "isolated/version"
-require_relative "isolated/isolated"
+require "rcee/isolated/isolated"
 
 module RCEE
   module Isolated

packaged_source/lib/rcee/packaged_source.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require_relative "packaged_source/version"
-require_relative "packaged_source/packaged_source"
+require "rcee/packaged_source/packaged_source"
 
 module RCEE
   module PackagedSource

packaged_tarball/lib/rcee/packaged_tarball.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require_relative "packaged_tarball/version"
-require_relative "packaged_tarball/packaged_tarball"
+require "rcee/packaged_tarball/packaged_tarball"
 
 module RCEE
   module PackagedTarball

precompiled/lib/rcee/precompiled.rb

@@ -5,7 +5,7 @@
 begin
   # load the precompiled extension file
   ruby_version = /(\d+\.\d+)/.match(::RUBY_VERSION)
-  require_relative "precompiled/#{ruby_version}/precompiled"
+  require "rcee/precompiled/#{ruby_version}/precompiled"
 rescue LoadError
   # fall back to the extension compiled upon installation.
   # use "require" instead of "require_relative" because non-native gems will place C extension files

system/lib/rcee/system.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require_relative "system/version"
-require_relative "system/system"
+require "rcee/system/system"
 
 module RCEE
   module System