fix: add -Wno-vla-extension (note, -Wno-vla-cxx-extension might be needed in the future)

[avivajpeyi]

@SimonStevenson is getting some new warnings when building

I am getting a new compiler warning with latest dev
warning: unknown warning option '-Wno-vla-cxx-extension'; did you mean '-Wno-vla-extension'? [-Wunknown-warning-option]

I see several new warnings when compiling COMPAS with latest dev:
Log.cpp:1323:22: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
1323 | bool buf[bufSize];
| ^~~~~~~
Log.cpp:1323:22: note: read of non-const variable 'bufSize' is not allowed in a constant expression
Log.cpp:1272:13: note: declared here
1272 | size_t bufSize = p_H5file.dataSets[p_DataSetIdx].buf.size(); // size of write buffer
| ^
Log.cpp:1329:27: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
1329 | short int buf[bufSize];
| ^~~~~~~
Log.cpp:1329:27: note: read of non-const variable 'bufSize' is not allowed in a constant expression
Log.cpp:1272:13: note: declared here
1272 | size_t bufSize = p_H5file.dataSets[p_DataSetIdx].buf.size(); // size of write buffer
| ^
Log.cpp:1336:21: warning: variable length arrays in C++ are a Clang extension [-Wvla-cxx-extension]
1336 | int buf[bufSize];
| ^~~~~~~
Log.cpp:1336:21: note: read of non-const variable 'bufSize' is not allowed in a constant expression
Log.cpp:1272:13: note: declared here
1272 | size_t bufSize = p_H5file.dataSets[p_DataSetIdx].buf.size(); // size of write buffer

I think we need different flags based on clang versions....
Clang < 17 → -Wno-vla-extension
Clang ≥ 17 → -Wno-vla-cxx-extension

(for context -- my Jetbrains IDE is what suggested me to use Wno-vla-cxx-extension in place of Wno-vla-extension

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[avivajpeyi]

Hey @jeffriley -- lets just foget about the changing flag for clang>18 for now? Ive left a comment in case this becomes an issue in the future.

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[jeffriley]

Thanks @avivajpeyi !

A few questions:

Why have you added -Wno-sign-compare? I think if we are generating these warnings we should fix the code - I know sometimes it's easier just to ignore the warning (or turn it off), but comparing a signed int to an unsigned (even size_t) is a bit of a code smell imo.

You've added -Wno-unused-variable - we should remove any unused variables, not just ignore their presence.

You've added -Wno-unused-parameter. Are you seeing any of these warnings (I'm not with gcc on linux)? For C++17 and later we can add the [[maybe_unused]] attribute. Not sure if that's available in clang (but I suspect it would be).

Ditto for -Wno-unused-function - although tbh we should remove any unused functions - if we find we need them later we can reinstate them from github.

You've added -Wno-reorder-ctor. Are you seeing any of these warnings (I'm not with gcc on linux)? If you are, we should fix the code - that's a bit of a code smell imo, and could cause problems in the future if there's a dependency on member initialisation.

[avivajpeyi]

OK -- lets just remove the extra warning-surpressment

[jeffriley]

Great - that works :-) Thanks!

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