Fix compilation on Windows.
Merge pull request #75 from schutm/master

Fix compilation on Windows.
Correct test for Windows (hopefully) that makes make on Linux work again
Adds missing closing bracket to eunit instructions
Merge pull request #76 from sedrik/patch-1

Adds missing closing bracket to eunit instructions
Force use of GNU Make on FreeBSD

The Makefile is not compatible with BSD make, and will produce the
following error when used on FreeBSD:

  Error expanding embedded variable.
  ERROR: Command [compile] failed!

Also, os:type/0 will probably never return a generic "bsd" as the
operating system: according to os(3), the value from "uname -s" will be
used.
Merge pull request #77 from olgeni/bsdmake

Force use of GNU Make on FreeBSD
Fix checking for bitstring instance