Alias init functions

The extension library has each initialization function named "Init_" +
basename. If multiple extensions have the same base name (such as
cgi/escape and erb/escape), the same function will be registered for
both names.

To fix this conflict, rename the initialization functions under sub
directories using using parent names, when statically linking.

ext/extmk.rb

@@ -132,6 +132,14 @@ def extract_makefile(makefile, keep = true)
   true
 end
 
+def create_makefile(target, srcprefix = nil)
+  if $static and target.include?("/")
+    base = File.basename(target)
+    $defs << "-DInit_#{base}=Init_#{target.tr('/', '_')}"
+  end
+  super
+end
+
 def extmake(target, basedir = 'ext', maybestatic = true)
   FileUtils.mkpath target unless File.directory?(target)
   begin
@@ -544,7 +552,13 @@ extend Module.new {
   end
 
   def create_makefile(*args, &block)
-    return super unless @gemname
+    unless @gemname
+      if $static and (target = args.first).include?("/")
+        base = File.basename(target)
+        $defs << "-DInit_#{base}=Init_#{target.tr('/', '_')}"
+      end
+      return super
+    end
     super(*args) do |conf|
       conf.find do |s|
         s.sub!(%r(^(srcdir *= *)\$\(top_srcdir\)/\.bundle/gems/[^/]+(?=/))) {

template/extinit.c.tmpl

@@ -1,5 +1,5 @@
 %# -*- C -*-
-% extinits = ARGV.map {|n| [n[%r[[^/.]+(?=\.[^/]*)?\z]], n]}
+% extinits = ARGV.map {|n| [n.tr('/', '_'), n]}
 #include "ruby/ruby.h"
 
 #define init(func, name) {	\