hi,

i just discovered that nettle in fedora/centos does not include the secp192 and 224 curves.

this is not discovered during build, but instead just leads to a runtime error. (the installation succeeds despite the error)

to make building pike work properly, the absence of these needs to be tested, so the code referencing them can be skipped.

i verified that, removing the references to those curves makes pike run without error, though i am not sure if this should be a compile option or if automatic detection is better.

greetings, martin.