MFC r346571,r346572:

Update the spelling of my name

Previous spellings of my name (NGie, Ngie) weren't my legal spelling. Use Enji
instead for clarity.

While here, remove "All Rights Reserved" from copyrights I "own".

MFC r319010:

Fix #if conditional added in r319008

I committed an earlier version of the file by accident

This is a no-op on ^/head and ^/stable/11.

MFC r319008:

kvm_geterr_test: Compile out the portions that require kvm_open2(3) on
systems that lack the libcall, based on __FreeBSD_version.

kvm_open2(3) wasn't made available until r291406, which is in ^/stable/11,
but not ^/stable/10. This makes some of kvm_geterr_test available for testing
on ^/stable/10.

MFC r316099:

lib/libkvm: start adding basic tests for kvm(3)

- kvm_close: add a testcase to verify support for errno = EINVAL / -1
(see D10065) when kd == NULL is provided to the libcall.
- kvm_geterr:
-- Add a negative testcase for kd == NULL returning "" (see D10022).
-- Add two positive testcases:
--- test the error case using kvm_write on a O_RDONLY descriptor.
--- test the "no error" case using kvm_read(3) and kvm_nlist(3) as
helper routines and by injecting a bogus error message via
_kvm_err (an internal API) _kvm_err was used as there isn't a
formalized way to clear the error output, and because
kvm_nlist always returns ENOENT with the NULL terminator today.
- kvm_open, kvm_open2:
-- Add some basic negative tests for kvm_open(3) and kvm_open2(3).
Testing positive cases with a specific
`corefile`/`execfile`/`resolver` requires more work and would require
user intervention today in order to reliably test this out.

lib/libkvm: start adding basic tests for kvm(3)

- kvm_close: add a testcase to verify support for errno = EINVAL / -1
(see D10065) when kd == NULL is provided to the libcall.
- kvm_geterr:
-- Add a negative testcase for kd == NULL returning "" (see D10022).
-- Add two positive testcases:
--- test the error case using kvm_write on a O_RDONLY descriptor.
--- test the "no error" case using kvm_read(3) and kvm_nlist(3) as
helper routines and by injecting a bogus error message via
_kvm_err (an internal API) _kvm_err was used as there isn't a
formalized way to clear the error output, and because
kvm_nlist always returns ENOENT with the NULL terminator today.
- kvm_open, kvm_open2:
-- Add some basic negative tests for kvm_open(3) and kvm_open2(3).
Testing positive cases with a specific
`corefile`/`execfile`/`resolver` requires more work and would require
user intervention today in order to reliably test this out.

Reviewed by: markj
MFC after: 2 months
Sponsored by: Dell EMC Isilon
Differential Revision: D10024