The IsLanguageEmpty algorithm returned wrong result (the opposite boolean) because of wrong use of the set::count method. Also use set::contains to make the code clearer.

So we easily know what version of cppcheck and clang-tidy
are we running. Compiler version is announced by CMake.

Recently we moved infrastructure repositories under a new path. Docker
registries have therefore moved too.  Reflect this in our CI settings.

Tomáš Pecka authored 4 years ago and Tomáš Pecka committed 4 years ago

Fixes a bug where wrong CMake variable was checked. Instead of checking
for existence of variable VERSION_STRING the code checked for existence
of variable "value_of(VERSION_STRING)".

tailing return type specification caused infinite template instantiation

This reverts commit dcf2c79a.