AGG 2.4 uses modified BSD license, AGG 2.5 uses GPL license, AGG 2.7 uses MIT license:
"License
MIT License"
https://sourceforge.net/projects/agg/
Although the copying file uses the modified version of the BSD license, the README file says that the license is MIT:
https://sourceforge.net/p/agg/svn/HEAD/tree/agg-2.4/copying
https://sourceforge.net/p/agg/svn/HEAD/tree/agg-2.4/README
AGG forks on github, still use modified BSD license!