--- subtle-0.11.3224-xi.orig/Rakefile
+++ subtle-0.11.3224-xi/Rakefile
@@ -352,6 +352,11 @@ task(:config) do
       ret
     end
 
+    cflags, ldflags, libs = pkg_config("ruby")
+    @options["cflags"]   << " %s" % [ cflags ]
+    @options["ldflags"]  << " %s %s" % [ ldflags, libs ]
+    @options["extflags"] << " %s %s" % [ ldflags, libs ]
+
     # Check pkg-config for X11
     checking_for("X11/Xlib.h") do
       cflags, ldflags, libs = pkg_config("x11")
