pi@raspberrypi ~/src/msf3 $ bundle install
/home/pi/.rvm/rubies/ruby-2.1.5/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require': /home/pi/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/armv6l-linux-eabihf/digest/sha1.so: undefined symbol: rb_Digest_SHA1_Init - /home/pi/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/armv6l-linux-eabihf/digest/sha1.so (LoadError)

pi@raspberrypi ~/src/msf3 $ readelf -Ws  /home/pi/.rvm/rubies/ruby-2.1.5/lib/ruby/2.1.0/armv6l-linux-eabihf/digest/sha1.so|grep rb_Digest_SHA1_Init
     8: 00000000     0 NOTYPE  GLOBAL DEFAULT  UND rb_Digest_SHA1_Init
    96: 00000000     0 NOTYPE  GLOBAL DEFAULT  UND rb_Digest_SHA1_Init