Os X Frontend development: Why sending SIGTERM?

Hi

I am currently trying to continue the work on Irssix, a Cocoa Mac Os X 
frontend to irssi. The developer who started the work has discontinued 
the project because of his lack of time.

Fo far, the irrsi code base seems very clean and the signal/slot system 
seems to make writing extensions and other frontends different from 
textual ones pretty simple.

However, Using the latest source release (0.8.9) the program "crashes" 
with SIGABRT on the start process... As far as I could track the error, 
the function "init_configfile" (defined in settings.c) always sends a 
SIGTERM "signal()" in line 705:

-8<---------

678 static void init_configfile(void)
679 {

// other stuff here

703 }
704
705 signal(SIGTERM, sig_term);
706 }

-8<---------

This results in the following console output when I try to run my 
program:

-8<---------

... other debug output here that I use to track what's going on
irssix (Upgraded) has exited due to signal 6 (SIGABRT).

-8<---------

What is the reason for this? Should the code ever reach there? Or does 
the BSD (Os X) signal differ from the one linux or other Unices? Or 
could my compiler (Xcode, using gcc as far as I can see) be the reason 
for this?

Maybe this is a stupid question, but I am pretty new to C and Unix 
programming (although not to programming in general). Do you have an 
idea?

Regards

Manuel Holtgrewe