compiling into shared library: external functions

I'm trying to compile a set of m-files into a shared library:

mcc -B cpplib:libmylib -T exec:lib -v mymfile1.m mymfile2.m

Some of my m-files contain %#external and I'm getting undefined symbols error for those functions. During the compilation, I'm getting the following warning though:

Warning: MATLAB Compiler's "%#external" pragma will not be supported in the future. Instead, compile your C/C++ source file into a MEX library and add it to the deployment package.

However, I can not compile my C++ source file into a MEX library in run-time.

When I use -T compile:lib flag, no shared library is created, only CTF archive, but I'm not sure how I can use it.

I'm using MATLAB Compiler 2014a. For the previous versions there were no such problems.