我的目标是使用libmspack。它依赖于ffi-compiler，我已经fork了ffi-compiler，添加了一些自定义代码，并且我希望libmspack使用我的修改版。 我有一个简单的Gemfile：
source 'http://rubygems.org'
gem 'ffi-compiler', :github =>'survili/ffi-compiler'
gem 'libmspack'
在运行 'bundle install' 时，'ffi-compiler' 的安装完成了，但是 'libmspack' 安装失败了，并且出现了一个错误，它找不到 'ffi-compiler'。(LoadError: cannot load such file -- ffi-compiler/compile_task)。我注意到如果从 Gemfile 中删除 'libmspack'，并尝试使用 'bundle exec install libmspack' 进行安装，它可以正常工作。有人能解释一下，实现我的目标的正确方法是什么，使 libmspack 使用自定义 ffi-compiler gem？我在这个 SO 帖子中发现了同样的问题，但没有答案: Gem::LoadError when using a git repo in Gemfile。谢谢您提前的帮助。
------ bundle 的输出（使用 RVM 的空 gemset）-------
jackju at macbook-air ~/tmp/delme1
$ rvm use 2.1.1@stackoverproblem --create
ruby-2.1.1 - #gemset created /home/jackju/.rvm/gems/ruby-2.1.1@stackoverproblem
ruby-2.1.1 - #generating stackoverproblem wrappers...........
Using /home/jackju/.rvm/gems/ruby-2.1.1 with gemset stackoverproblem
jackju at macbook-air ~/tmp/delme1
$ rvm current
ruby-2.1.1@stackoverproblem
jackju at macbook-air ~/tmp/delme1
$ vim Gemfile
[1]+ Stopped vim Gemfile
jackju at macbook-air ~/tmp/delme1
$ rvm current
ruby-2.1.1@stackoverproblem
jackju at macbook-air ~/tmp/delme1
$ gem list
*** LOCAL GEMS ***
bigdecimal (1.2.4)
bundler (1.5.3)
bundler-unload (1.0.2)
executable-hooks (1.3.1)
gem-wrappers (1.2.4)
io-console (0.4.2)
json (1.8.1)
minitest (4.7.5)
psych (2.0.3)
rake (10.1.0)
rdoc (4.1.0)
rubygems-bundler (1.4.2)
rvm (1.11.3.9)
test-unit (2.1.1.0)
jackju at macbook-air ~/tmp/delme1
$ bundle
Fetching git://github.com/survili/ffi-compiler.git
remote: Reusing existing pack: 260, done.
remote: Counting objects: 5, done.
remote: Compressing objects: 100% (5/5), done.
remote: Total 265 (delta 2), reused 0 (delta 0)
Receiving objects: 100% (265/265), 38.59 KiB | 0 bytes/s, done.
Resolving deltas: 100% (116/116), done.
Fetching gem metadata from http://rubygems.org/.........
Fetching additional metadata from http://rubygems.org/..
Resolving dependencies...
Installing rake (10.3.1)
Installing ffi (1.9.3)
Using ffi-compiler (0.1.4) from git://github.com/survili/ffi-compiler.git (at master)
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
/home/jackju/.rvm/rubies/ruby-2.1.1/bin/ruby -rubygems /home/jackju/.rvm/gems/ruby-2.1.1@stackoverproblem/gems/rake-10.3.1/bin/rake RUBYARCHDIR=/home/jackju/.rvm/gems/ruby-2.1.1@stackoverproblem/extensions/x86_64-linux/2.1.0/libmspack-0.0.4 RUBYLIBDIR=/home/jackju/.rvm/gems/ruby-2.1.1@stackoverproblem/extensions/x86_64-linux/2.1.0/libmspack-0.0.4
rake aborted!
LoadError: cannot load such file -- ffi-compiler/compile_task
/home/jackju/.rvm/gems/ruby-2.1.1@stackoverproblem/gems/libmspack-0.0.4/ext/Rakefile:1:in `<top (required)>'
(See full trace by running task with --trace)
rake failed, exit code 1
Gem files will remain installed in /home/jackju/.rvm/gems/ruby-2.1.1@stackoverproblem/gems/libmspack-0.0.4 for inspection.
Results logged to /home/jackju/.rvm/gems/ruby-2.1.1@stackoverproblem/extensions/x86_64-linux/2.1.0/libmspack-0.0.4/gem_make.out
An error occurred while installing libmspack (0.0.4), and Bundler cannot
continue.
Make sure that `gem install libmspack -v '0.0.4'` succeeds before bundling.
jackju at macbook-air ~/tmp/delme1
$ ls
Gemfile
jackju at macbook-air ~/tmp/delme1
$