i am not sure, if this solves your problem, but for me it worked:
Disable SRTP (Secure Real-Time Transport Protocol)
Add the following to the file pjlib/include/pj/config_site.h
#define PJMEDIA_HAS_SRTP 0
make again - should work.
The right solution would be to reimplement the missing structure in the c code. Probably better to wait for a patch.