Dynamic linking bugfix

[zfogg]

Confirmed working for both OS X (El Capitan) and Linux (Ubuntu LTS)

This fixes #3597 and fixes #3459.

About the Linux dynamic linking setup.. perhaps it would be better practice if we added libcaffe to the OS's dynamic library cache? We could do something like this:

~/src/caffe$ ldconfig -r $HOME -p ./build/lib
~/src/caffe$ ldconfig -p | grep caffe
        libcaffe.so.1.0.0-rc3 (libc6,x86-64) => /home/ubuntu/src/caffe/build/lib/libcaffe.so.1.0.0-rc3
        libcaffe.so (libc6,x86-64) => /home/ubuntu/src/caffe/build/lib/libcaffe.so

So, it works well right now using ld.so's magic '$ORIGIN' variable, but maybe switching to ldconfig is the right move. Any preference? Let me know! :)

[lukeyeager]

Your fix doesn't seem to work on TravisCI (Ubuntu 12.04).

This comment might be relevant/helpful:

I'm not sure how the linking bug was introduced, but running the following two lines after make alland make test fixes the problem for good:

install_name_tool -change libcaffe.so.1.0.0-rc3 @executable_path/../lib/libcaffe.so.1.0.0-rc3 .build_release/tools/caffe
install_name_tool -change libcaffe.so.1.0.0-rc3 @executable_path/../lib/libcaffe.so.1.0.0-rc3 .build_release/test/test_all.testbin

@safrooze #3597 (comment)

[zfogg]

hacking away at the issue.. p sure I know what the problem is; please hold and I'll push a fix :)

[shelhamer]

Thanks for taking a stab at a fix @zfogg but this is addressed by smaller patches in #3695 and #3696. If there are further cmake changes you would like to contribute please open a separate PR.