Latest update of Oberdiek package: \declaretheoremstyle not working anymore

As part of The Big Oberdiek Split™, the kvsetkeys package (loaded by thmtools) was removed from the Oberdiek bundle, and the etexcmds package was removed from kvsetkeys (probably because its usefulness is debatable) in this commit, so thmtools, which relied on kvsetkeys loading etextools now breaks. That is one of the reasons why relying on a package loading another package is a bad idea: if you need the package, load it.

That said, as a workaround until thmtools is fixed, you can load etexcmds manually.

I uploaded a fixed version to CTAN that takes the dependency out, but it will take a couple of days to arrive.

I don't consider myself the maintainer of the package though ... so anyone really interested in this package please consider taking on the maintenance. I'm already doing support for too many packages that aren't mine.