* common.mk: use -lsocket -liconv -lgen on Illumos/Solaris * mkdirp: return int and accept a mode argument * use i3's mkdirp on everything except Illumos
* common.mk: use -lsocket -liconv -lgen on Illumos/Solaris * mkdirp: return int and accept a mode argument * use i3's mkdirp on everything except Illumos