1 files changed, 24 insertions, 0 deletions
diff --git a/ext/ripper/extconf.rb b/ext/ripper/extconf.rb
new file mode 100644
index 0000000000..536e23d3ad
--- /dev/null
+++ b/ext/ripper/extconf.rb
@@ -0,0 +1,24 @@
+#!ruby -s
+
+require 'mkmf'
+require 'rbconfig'
+
+def main
+  unless have_command('bison')
+    $stderr.puts 'Ripper requires bison; abort'
+    exit 1
+  end
+  $objs = %w(ripper.o)
+  $cleanfiles.concat %w(ripper.y ripper.c ripper.output ids1 ids2)
+  $CPPFLAGS += ' -DRIPPER'
+  $CPPFLAGS += ' -DRIPPER_DEBUG' if $debug
+  create_makefile 'ripper'
+end
+
+def have_command(cmd)
+  ENV['PATH'].split(File::PATH_SEPARATOR).any? {|path|
+    File.executable?("#{path}/#{cmd}#{Config::CONFIG['EXEEXT']}")
+  }
+end
+
+main