dub.sdl: Use compiler specific `-preview=in`. Disable it for GDC. ...

Having `-preview=in` in dflags without a platform specification
leads to errors with gdc:
```
gdc: error: unrecognized command-line option ‘-preview=in’; did you mean ‘-fpreview=in’?
```

However, using the proper `-fpreview=in` for gdc causes an ICE:
```
/usr/lib/gcc/x86_64-pc-linux-gnu/13/include/d/std/math/exponential.d:587:30: internal compiler error: in layout_aggregate_type, at d/types.cc:562
  587 |             enum maxOdd = pow(2.0L, real.mant_dig) - 1.0L;
```

Leave `-preview=in` enabled for dmd and ldc and wait for a fix
before enabling it for gdc.

Signed-off-by: Andrei Horodniceanu <a.horodniceanu@proton.me>

Build with -preview=in ...

This reduces the number of deprecations issued in dub.

Silence a trivial deprecation when doing dub test

Revert "Remove Vibe.d HTTP support / library-nonet" ...

This reverts commit db49cbe.

Fix #2512: Remove hard dependency on libcurl ...

It's no longer needed as Phobos loads it dynamically.

Remove Vibe.d HTTP support / library-nonet ...

library-nonet has been broken for years, and is not used.
Most importantly, it has no support for timeout.
Lastly, the likely reason it was originally introduced was to
avoid a hard dependency on cURL, something that has been fixed
in Phobos directly.

Trivial: Make more obvious to developers how to debug YAML parsing ...

This might not be obvious to developers, and the name might not
stick, so just add a comment for future users.

Raise minimum Vibe.d requirement to v0.9.0 ...

Make sure a recent enough Vibe.d is used so we can update the vibecompat code.
Additionally, since the split of Vibe.d into package, and the splitting of
vibe-core into its own project, the version specification was never triggered,
so it was corrected in this commit (the version spec was correct for older Vibe.d).

Update taggedalgebraic, eventcore, vibe-core, vibe.d dependencies

implement $DUB build variable ...

fix localized import


do not escape DUB path

DUB_EXE in script environment

Update author list based on amount of contributions.

Skip explicitly linking with libcurl. ...

libcurl is loaded dynamically by Phobos and static linking results in the wrong import library being passed to LDC on Windows.

Allow the optional vibe-d dependency to match 0.8.x.

Restore optional attribute of vibe-d dependency.

Fix vibe.d compatibility for vibe.d < 0.8.0.

Use a sub package dependency for vibe-d.

Update DUB recipe and convert to more readable SDLang.