Oracle Developer Studio 12.6 fixes

[k0ekk0ek]

The compiler has problems with getopt (not technically necessary for NSD), so the configure checks need to be extended a little bit. Apart from that, the functions need unit tests to verify they do exactly as required because and to verify they don't introduce extra work. Work-in-progress.

[k0ekk0ek]

Compile under Oracle Developer Studio 12.6 still fails because tempnam is missing. It's used only in tests, but we needed to use another function for that because of warnings anyway, so fixing that next. Still need to add tests to verify correct operation of lower level functions like trailing_zeroes etc.

[k0ekk0ek]

Well it builds and runs if I compile using Oracle Developer Studio 12.6. Now to add tests etc.

[k0ekk0ek]

Still some warnings when compiling with developer studio, but builds and tests all run.

[k0ekk0ek]

Changes so far allow me to build for Solaris 10 (sparce and x86_64). Now going to test building NSD 4.10.

[k0ekk0ek]

Once NLnetLabs/nsd#351 is merged, simdzone compiles just fine. At least, with GCC. simdzone builds just fine with Developer Studio 12.4 too, but NSD itself does not. Verified for x86 and Sparc using build infrastructure from https://www.opencsw.org/.

See log:
solaris.build.log

[k0ekk0ek]

Quick push to resolve merge issues. Should be all good now.

[wcawijngaards]

Many changes, but it is nice to increase the portability. There are added tests for the compat simd implementations.