I am building my application for iOS6 and i want to support armv6 so i had added the armv6 in architecture and valid architecture. Now application is giving lot of errors when build on apple llvm 4.1 but it compiles on llvm gcc 4.2. And when i build an Adhoc app using llvm gcc 4.2 then it's not installing on iphone 3GS and ipod 3G.
It's possible as kenji has given a link in the accepted Answer