[Swarm-support] MinGW also no longer easy to use with Swarm

[Steve Railsback]

On my new computer, I installed the latest version of Msys and MinGW, 
the Unix-like environment and compiler that let you compile Windows 
executables of Swarm models:
http://www.swarm.org/wiki/Swarm_and_MinGW

I did not however pay attention to what version of the gcc compiler it 
contains, being just happy that my Swarm code would compile and run.

But eventually I noticed that my model results did not correspond with 
those produced on other machines... it turns out MinGW now comes with 
gcc 6.*, whereas Swarm is happy with <= 4.6. It produced code that ran 
but produced bad results.

There are very simple, easy instructions on the web for replacing the 
MinGW compiler with an older version of gcc, but when I tried it the 
system could no longer even find the compiler.

There are also on the web old versions of MinGW, but no explanation of 
how to install and use them, and I failed at that too.

But I did learn that you can just copy an old version from one computer 
to another, and it works. The programs are not really installed in the 
Windows registry.

So I put a version of MinGW that has a compiler compatible with Swarm on 
my web page:
http://www.langrailsback.com/SwarmVM/
and put a note about it on the Swarm wiki.

Steve R.

--
Steve Railsback
Lang Railsback & Associates
Arcata, California
www.LangRailsback.com
www.railsback-grimm-abm-book.com