SIP library for iOS with non-GPL license

These are the ones I know about:

Proprietary:

• vaxvoip

Open source: GPL/LGPL

• sofia-sip
• linphone
• exosip

oSIP is LGPL and therefore can be used (as a library) in commercial and closed-source projects. It compiles easily for arm. It is the SIP library used by linphone for iPhone; however, linphone is GPL.