Fixed 10.4 compilation problem in objc runtime extensions.
Fixed 10.4 compilation problem in objc runtime extensions.

gcbeyond/nu,nulang/nu,heiko-henrich/nutor,hodgeswt/nu,heiko-henrich/nutor,spotify/nu,alloy/nu,jqk6/nu,gcbeyond/nu,gcbeyond/nu,nulang/nu,hodgeswt/nu,hodgeswt/nu,spotify/nu,gcbeyond/nu,jqk6/nu,heiko-henrich/nutor,jsyedidia/nu,jsyedidia/nu,jsyedidia/nu,heiko-henrich/nutor,spotify/nu,jqk6/nu,timburks/nu,hodgeswt/nu,alloy/nu,spotify/nu,nulang/nu,jqk6/nu,jsyedidia/nu,jsyedidia/nu,timburks/nu,timburks/nu