This is because there is no netgroup.h on Solaris.
In reading the man pages for *netgrent on Solaris, Linux and OSX, none say netgroup.h is required.
Proposed patch to remove the reference is included. The wscript change is a guess because I do not use waf.
Created attachment 5814 [details]
I suspect this regression came from, 7a1c2470, which I tracked back to you.
Could you please review what I have here, and work with me to get a fix into the tree?
Sorry, this will break the NetBSD5 box in the build farm. I had to add that additional header to get the prototypes on NetBSD. We obviously need a more complicated check. This patch won't work as is, though.
Created attachment 5819 [details]
Attempt to fix *netgrent prototype detection on Solaris
Please check if this patch works for you on Solaris.
Looks good from here Kai. It passes build here.
Fixed in master by commit 0b6cebd60288b37f28176e24abeb20109dfd70e5 then.