PJSIP is open source SIP, Media and NAT traversal library (www.pjsip.org)
This is a prebuild pjsip library included universal libraries for armv7, armv7s, arm64, iPhoneSimulator
This fork supports SSL.
This fork binaries built using iOS7.0 SDK
The best way is using cocoapods.
Check the Podfile configuration:
platform :ios, '7.0'
pod 'pjsip', :path => '~/path/to/this/checkout'
and run pod install
git submodule init
git submodule update # for ios-openssl
./build.sh # (starts fresh)