uname on SmartOS cannot be used to guess if 32 and/or 64 bits binaries
are supported, and its output is different than other uname commands on
other operating systems.
This change uses pkg_info to determine what types of binaries pkgsrc
would install. If pkg_info fails to run or is not present, this change
falls back to using isainfo -n, which determines what the kernel
supports.
It allows users to install node binaries on Solaris derivatives. io.js
can also be installed on Solaris derivatives starting with version
v3.3.1.
Qiangjun Ran