cmake: added target compile option -ffile-prefix-map
- remove the ${CMAKE_SOURCE_DIR} and path to modules from __FILE__
define
- the CMake provides absolute path to compiler, resulting in very long
log messages when left without this option, like:
DEBUG: <core> [/home/ubuntu/work/kamailio-dev/src/core/sr_module.c:915]: ...
DEBUG: htable [/home/ubuntu/work/kamailio-dev/src/modules/htable/ht_var.c:193]: ...
- this option should make it like it is with the old-makefiles
DEBUG: <core> [core/sr_module.c:915]: ...
DEBUG: htable [ht_var.c:193]: ...