Since finding the pre-compiled SPARC binaries at solarisvoip.com/ I’ve not bothered going through all the hoops to get Asterisk compiled on Solaris.
BTW, they have x86 and x64 versions too.
The only thing to add is the solution to a Solaris 10 manifest issue which I posted to their alias as follows:
Firstly, when installing Asterisk the manifest doesn’t get imported automatically so you need to run
svc:> import /var/svc/manifest/application/asterisk-smf.xml
svc:> import /var/svc/manifest/application/zaptel-smf.xml
Secondly, even when installed Asterisk does not start properly after a reboot because of incorrect dependancies, which can be corrected as follows
svc:> select svc:/application/voip/server:default
svc:/application/voip/server:default> setprop dependents/asterisk-network = fmri: svc:/milestone/network:default
Now, it all restarts correctly after a reboot.