Fix SmartOS compilation once and for all

[mgreter]

Verified by compiling inside VMWare image (the problems with SEC were present):

SunOS smartos 5.11 joyent_20160108T173524Z i86pc i386 i86pc

Let's see what CI thinks ... #1802

[mgreter]

The last commit reverts the SunOS specifics in the Makefile:

1) We need to have libtool installed and ginstall is not available by default too!
2) We install to / on all platforms (use PREFIX="/opt/local" make to override).

SmartOS needs: pkgin install automake autoconf libtool!
Then we can also build libsass via autotools as documented.

[xzyfer]

@jaredmorrow @djensen47 I'd like to hear your thoughts here

[mgreter]

Looks like ginstall would still be the correct one to use. libtool install doesn't seem to do the right thing, was asuming it would. But no idea how to get gnu-install on to SmartOS. Maybe if someone can argue why we cannot install into / on Solaris, please enlighten me.

Btw. install from libtools outputs:

find: cycle detected for /lib/crypto/32/
find: cycle detected for /lib/secure/32/
find: cycle detected for /lib/32/
find: cycle detected for /usr/lib/elfedit/32/
find: cycle detected for /usr/lib/libp/32/
find: cycle detected for /usr/lib/link_audit/32/
find: cycle detected for /usr/lib/lwp/32/
find: cycle detected for /usr/lib/secure/32/
find: cycle detected for /usr/lib/32/
install: libsass.a was not found anywhere!

¯_(ツ)_/¯

[mgreter]

Verfied both install methods and documented my findings. Very very sure this chapter can be closed!

[mgreter]

I'm going to merge this on my responsibility. Beside CI I have tested it with Visual Studio 2013 Community, SmartOS 5.11, Gentoo Linux, Cygwin and MinGW. Not all combinations, but a fair share.
Want to move forward and concentrate to bring sass 3.4.21 parity!
As always feel free to open issues when problems arise.
Have a nice day!