diff --git a/dist/jruby.rake b/dist/jruby.rake
index ea13f57..22e49c3 100644
--- a/dist/jruby.rake
+++ b/dist/jruby.rake
@@ -1,5 +1,5 @@
 file pkg("foreman-#{version}-jruby.gem") => distribution_files do |t|
-  sh "env JRUBY=true gem build foreman.gemspec"
+  sh "env PLATFORM=jruby gem build foreman.gemspec"
   sh "mv foreman-#{version}-java.gem #{t.name}"
 end
 
diff --git a/foreman.gemspec b/foreman.gemspec
index db6f295..5e6ee36 100644
--- a/foreman.gemspec
+++ b/foreman.gemspec
@@ -19,7 +19,7 @@ Gem::Specification.new do |gem|
   gem.add_dependency 'term-ansicolor', '~> 1.0.7'
   gem.add_dependency 'thor',           '>= 0.13.6'
 
-  if ENV["JRUBY"]
+  if ENV["PLATFORM"] == "jruby"
     gem.add_dependency "posix-spawn", "~> 0.3.6"
     gem.platform = Gem::Platform.new("java")
   end