Fix some build warnings and a multithread warning, when building with…

[thomasmey]

… -T 1C

[jansupol]

Thank you for contribution. It looks good. Except, can you please update the copyright year in the modified files?

[thomasmey]

hi, yes can do, but one question, what does it mean that there are two years, e.g.:
"Copyright (c) 2015, 2018..."

In what should I change it?
a.) Copyright (c) 2020
b.) Copyright (c) 2015, 2020
c.) Copyright (c) 2015, 2018, 2020

I think this copyright notice is only relevant for US law only?!

Also this seems to indicate that the notice is even not necessary any more at all:
https://en.wikipedia.org/wiki/Copyright_symbol
but OTOH IANAL!

[jansupol]

We use two years, the year of creation and the year of the last change. So option B, please.

The Eclipse Foundation says:

{DATE} is either a year or a range of years with the first and last years of the range separated by a comma. So for example: "2004" or "2000, 2004". The first year is when the contents of the file were first created and the last year is the last year is when the contents were last modified.