We used to export 'LC_COLLATE=C' for the environment of Genode tools. This was
meant to ensure that sorting is always done C-style and not dependent on the
users locale settings. This is required, for instance, to ensure that the same
archive always yields the same hash.
However, 'export LC_COLLATE=C' is not sufficient. It can be outruled by an
'LC_ALL' setting in the users environment. The manual of 'sort' recommends to
set 'LC_ALL=C' locally if you want reliable results and this is what this
commit does. Furthermore it removes the former 'export LC_COLLATE=C'
directives.
Note that I couldn't find a way to set 'LC_ALL' local to 'exec ... sort' in
TCL. This is why I set it global instead using TCLs 'env' array.
Note that the Make directive '$(sort ...)' and the TCL directive 'lsort',
unlike the Shell directive 'sort', are not affected by the users locale
settings.
Fixes#4144
This patch prevents the abi_symbols tool from generating symbols that
are known to occur in shared objects but must not be part of a library
ABI. This saves a bit of time during library-porting work.
However, to avoid the accidental use of ABI symbol definitions that lack
any form of manual curation, the abi_symbols tool outputs a special
message, which is explicitly checked-for by the check_abi tool.
Fixes#3112
