nixpkgs/pkgs/development/ruby-modules/gem-config/rdiscount-use-nixpkgs-libmarkdown.patch

diff --git a/ext/extconf.rb b/ext/extconf.rb
index 30764cb..b87ac2b 100644
--- a/ext/extconf.rb
+++ b/ext/extconf.rb
@@ -46,4 +46,9 @@ if /mswin/.match RbConfig::CONFIG['host_os']
   $defs.push("-Dinline=__inline")
 end
 
+$srcs = %w[
+  rdiscount.c
+]
+have_library('markdown')
+
 create_makefile('rdiscount')