The fmt library happily accepts std::string without
any conversions.

Fixes multiple copyright messages in the doxygen docu.

ag '\\file' -L --ignore=ThirdParty *Lib |xargs  sed -i 's/\(.*\)\\copyright/\1\\file\n\1\\copyright/'

Clang format run on near-the-header lines.

Happy New Year

Automatically with sed
sed -i 's/ogs_file_param_attr{process/ogs_file_param_attr{prj__processes__process/g'
and similar to the ogs_file_param_special and the ogs_file_param
doxygen commands.

# remove #pragma once:
grep -r --include=*.h -Fx '#pragma once' -l . \
| while read f; do
    hg="`realpath --relative-to=. "$f" | tr '/.[:lower:]' '__[:upper:]'`"
    sed -i -e "/#pragma once/ c \\
#ifndef $hg\\
#define $hg
$ a \\
\\
#endif  // $hg" "$f";
done