Some improvements to Autotools.

[besser82]

Basically this adds some sanity checks in configure around the regen-test-crypt-kat target in Makefile.

[codecov]

Codecov Report

Merging #82 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop      #82   +/-   ##
========================================
  Coverage    96.39%   96.39%           
========================================
  Files           32       32           
  Lines         3109     3109           
========================================
  Hits          2997     2997           
  Misses         112      112

Impacted Files	Coverage Δ
alg-yescrypt-opt.c	97.58% <0%> (-0.22%)	⬇️
crypt-nthash.c	89.28% <0%> (+3.57%)	⬆️

---

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[codecov-io]

Codecov Report

Merging #82 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop      #82   +/-   ##
========================================
  Coverage    96.39%   96.39%           
========================================
  Files           32       32           
  Lines         3109     3109           
========================================
  Hits          2997     2997           
  Misses         112      112

Impacted Files	Coverage Δ
crypt-pbkdf1-sha1.c	97.29% <0%> (-1.36%)	⬇️
crypt-sunmd5.c	99.07% <0%> (+0.92%)	⬆️

---

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Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0a7ada6...0f0c90a. Read the comment docs.

[besser82]

@zackw Are you fine with this change?

[besser82]

Rebased onto develop, squashed all previous commits into one.

[zackw]

This looks good. Sorry to keep you waiting, I was very busy the past couple days, and I always have to think carefully about changes to the configure script that are more complicated than adding another entry to the AC_CHECK_FUNCS list.

I have a few line notes but none of them is critical.

[besser82]

Fixes are in the rebased commit. Will merge on CLI as soon as Travis turns green.