add dev-cmd folder

Library/Homebrew/cmd/command.rb

@@ -3,7 +3,9 @@ module Homebrew
     cmd = ARGV.first
     cmd = HOMEBREW_INTERNAL_COMMAND_ALIASES.fetch(cmd, cmd)
 
-    if (path = HOMEBREW_LIBRARY_PATH/"cmd/#{cmd}.rb") && path.file?
+    if (path = HOMEBREW_LIBRARY_PATH/"cmd/#{cmd}.rb").file?
+      puts path
+    elsif ARGV.homebrew_developer? && (path = HOMEBREW_LIBRARY_PATH/"dev-cmd/#{cmd}.rb").file?
       puts path
     elsif (path = which("brew-#{cmd}") || which("brew-#{cmd}.rb"))
       puts path

Library/Homebrew/cmd/commands.rb

@@ -20,9 +20,11 @@ module Homebrew
 
   def internal_commands
     with_directory = false
-    (HOMEBREW_REPOSITORY/"Library/Homebrew/cmd").
-      children(with_directory).
-      map { |f| File.basename(f, ".rb") }
+    cmds = (HOMEBREW_LIBRARY_PATH/"cmd").children(with_directory).map { |f| File.basename(f, ".rb") }
+    if ARGV.homebrew_developer?
+      cmds += (HOMEBREW_LIBRARY_PATH/"dev-cmd").children(with_directory).map { |f| File.basename(f, ".rb") }
+    end
+    cmds
   end
 
   def external_commands

Library/brew.rb

@@ -106,7 +106,13 @@ begin
   # Add SCM wrappers.
   ENV["PATH"] += "#{File::PATH_SEPARATOR}#{HOMEBREW_LIBRARY}/ENV/scm"
 
-  internal_cmd = require? HOMEBREW_LIBRARY_PATH.join("cmd", cmd) if cmd
+  if cmd
+    internal_cmd = require? HOMEBREW_LIBRARY_PATH.join("cmd", cmd)
+
+    if !internal_cmd && ARGV.homebrew_developer?
+      internal_cmd = require? HOMEBREW_LIBRARY_PATH.join("dev-cmd", cmd)
+    end
+  end
 
   # Usage instructions should be displayed if and only if one of:
   # - a help flag is passed AND an internal command is matched