Log Message:
Fix detection of ccrtp (pkg-config file name changed for 2.x).

Build now dies in
log.cpp: In member function 'void t_log::write_header(const std::string&, \ 
t_log_class, t_log_severity)':
log.cpp:164:24: error: call of overloaded 'localtime_r(time_t*, tm*)' is ambiguous