Stop hardcoding python2.6 on SmartOS

- Stop hardcoding python2.6.
- Build with the arch reported by `uname -m` instead of the
  first arch listed in `file .../python`. This is my best
  guess as to the arch used by the system when launching a
  universal binary.
- Fix shebang lines in installed binaries to explicitly
  point to the Python for which we built.
work around broken pkg_alternatives in pkgsrc (internal DATASET-277)
fix build to work against 64-bit python on smartos (at least)
Fix build for when python runs in different bit-ness than `uname -m` on Mac.
Also clean up some whitespace.
use CFLAGS instead of CC for '-mNN'

…hon 2.7

…tible with python3 (TritonDataCenter#24)

This attempts to only use Python 2 -- looking for `which python2` first
in case `which python` is actually a Python 3.

Reviewed by: Dan McDonald <danmcd@kebe.com>

…nDataCenter#30)

Reviewed by: Dan McDonald <danmcd@kebe.com>