Create release against latest build of discount

[minorOffense]

2.1.7 is the current latest stable. Any chance of getting a release to include the updated code?

[minorOffense]

https://github.com/Orc/discount/tree/v2.1.7

[anthonyryan1]

Perhaps a better solution would be to dynamically link libdiscount, so that it can be used with any updated version as long as the API remains compatible.

[koenpunt]

I started a version with a dynamically linked version, but there are still some tests failing. https://github.com/koenpunt/php-discount

For this I already submitted some patches and suggestions to the discount repo, where @Orc is really playing along, which is great!