Installation problem on Mac OS X Lion

[alexspeller]

The gem won't install on OS X Lion:

$ gem install hornetseye-ffmpeg

Building native extensions.  This could take a while...
ERROR:  Error installing hornetseye-ffmpeg:
    ERROR: Failed to build gem native extension.

        "/Users/alex/.rbenv/versions/1.9.3-p392/bin/ruby" -rubygems /Users/alex/.rbenv/versions/1.9.3-p392/lib/ruby/gems/1.9.1/gems/rake-10.0.4/bin/rake RUBYARCHDIR=/Users/alex/.rbenv/versions/1.9.3-p392/lib/ruby/gems/1.9.1/gems/hornetseye-ffmpeg-1.1.1/lib RUBYLIBDIR=/Users/alex/.rbenv/versions/1.9.3-p392/lib/ruby/gems/1.9.1/gems/hornetseye-ffmpeg-1.1.1/lib
Please install 'yard' if you want to generate documentation
rake aborted!
Cannot find ByteIOContext member variable

Tasks: TOP => .depends.mf => config_h => ext/config.h
(See full trace by running task with --trace)


Gem files will remain installed in /Users/alex/.rbenv/versions/1.9.3-p392/lib/ruby/gems/1.9.1/gems/hornetseye-ffmpeg-1.1.1 for inspection.
Results logged to /Users/alex/.rbenv/versions/1.9.3-p392/lib/ruby/gems/1.9.1/gems/hornetseye-ffmpeg-1.1.1/./gem_make.out

ffmpeg details:

$ ffmpeg -version
ffmpeg version 1.2
built on Apr 21 2013 19:56:46 with Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn)
configuration: --prefix=/usr/local/Cellar/ffmpeg/1.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --enable-vda --cc=cc --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid
libavutil      52. 18.100 / 52. 18.100
libavcodec     54. 92.100 / 54. 92.100
libavformat    54. 63.104 / 54. 63.104
libavdevice    54.  3.103 / 54.  3.103
libavfilter     3. 42.103 /  3. 42.103
libswscale      2.  2.100 /  2.  2.100
libswresample   0. 17.102 /  0. 17.102
libpostproc    52.  2.100 / 52.  2.100