Fix project compilation on GCC compilers

[sndth]

This PR fixes an issue with project compilation on GCC compilers.
Looks like the newer GCC versions shows -Werror=deprecated-literal-operator when the project is building.

I prepared a simple fix that check whether compiler is __GNUC__ and the version is newer than 6.
If yes, a new macro - FK_YAML_QUOTE_OPERATOR will use operator""_yaml, otherwise operator"" _yaml.

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• The test suite compiles and runs without any error.
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[fktn-k]

@sndth
Thanks for dealing with this.
Taking a brief look at the changes, I guess you're using different version of clang-format.
Please use the script under scripts directory.

[sndth]

@sndth Thanks for dealing with this. Taking a brief look at the changes, I guess you're using different version of clang-format. Please use the script under scripts directory.

Oh exactly, I am using 20.1.4 but the project is using 18.1.3.
If you want, I can bump version of clang-format, because changes between these versions in case of this project are minimal.

[fktn-k]

@sndth Thanks for dealing with this. Taking a brief look at the changes, I guess you're using different version of clang-format. Please use the script under scripts directory.

Oh exactly, I am using 20.1.4 but the project is using 18.1.3. If you want, I can bump version of clang-format, because changes between these versions in case of this project are minimal.

Clang-format tools with different major versions would cause a lot of unrelated changes. Although bumping-up is ok, I'd say it's better to do so in a different PR.
Can you use scripts/run_clang_format.(sh|bat) which forces clang-format 18.1.3 for now?

[sndth]

@sndth Thanks for dealing with this. Taking a brief look at the changes, I guess you're using different version of clang-format. Please use the script under scripts directory.

Oh exactly, I am using 20.1.4 but the project is using 18.1.3. If you want, I can bump version of clang-format, because changes between these versions in case of this project are minimal.

Clang-format tools with different major versions would cause a lot of unrelated changes. Although bumping-up is ok, I'd say it's better to do so in a different PR. Can you use scripts/run_clang_format.(sh|bat) which forces clang-format 18.1.3 for now?

Yep! I just dropped commit with formatting changes and there is no files to reformat for now.

[fktn-k]

Looks good to me. Thanks!