During the building phase of my applications, sometimes I’ve got this error :
Undefined symbols for architecture armv6: "_main", referenced from: start in crt1.o ld: symbol(s) not found for architecture armv6
Last time, the solution was easy to find : this was just a missing file in the Build Phase > Compile Sources of the target I was building. I added main.m to the listing and the error was gone.
As simple as that !