finding isnan

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

math/py-scikit-learn currently doesn't build because it doesn't find
'isnan'.

As I understand it, that symbol should be available for C++ files from
C++11 onwards, so I tried adding 'c++11' to USE_LANGUAGES, but that
didn't help, even though -std=c++11 ended up on the compiler line.

http://www.ki.nu/pkgsrc/reports/current/NetBSD-9.0/20231104.1950/py310-scikit-learn-1.3.2/build.log

Any ideas?
 Thomas