I just did a rebootstrap on a fs box, it turned out the new revision has this at the end of mod_sofia.h:

char *sofia_glue_get_extra_headers(switch_channel_t *channel, const char *prefix);
<<<<<<< .mine
void sofia_glue_set_extra_headers(switch_channel_t *channel, sip_t const *sip, const char *prefix);

=======
void sofia_glue_set_extra_headers(switch_channel_t *channel, sip_t const *sip, const char *prefix);
>>>>>>> .r14490

no wonder why it wouldn't compile :P