* Implement Pandoc Markdown concise link extension
This implements https://github.com/nim-lang/Nim/issues/20127.
Besides reference to headings we also support doing references
to Nim symbols inside Nim modules.
Markdown:
```
Some heading
------------
Ref. [Some heading].
```
Nim:
```
proc someFunction*() ...
... ## Ref. [someFunction]
```
This is substitution for RST syntax like `` `target`_ ``.
All 3 syntax variants of extension from Pandoc Markdown are supported:
`[target]`, `[target][]`, `[description][target]`.
This PR also fixes clashes in existing files, particularly
conflicts with RST footnote feature, which does not work with
this PR (but there is a plan to adopt a popular [Markdown footnote
extension](https://pandoc.org/MANUAL.html#footnotes) to make footnotes work).
Also the PR fixes a bug that Markdown links did not work when `[...]`
section had a line break.
The implementation is straightforward since link resolution did not
change w.r.t. RST implementation, it's almost only about new syntax
addition. The only essential difference is a possibility to add a custom
link description: form `[description][target]` which does not have an
RST equivalent.
* fix nim 1.0 gotcha
* implement case for cstring
for now just converts to string on C backend
* custom implementation for cstring
* remove leftover
* revert even more
* add nil + fix packages weird variant literal bug
* update docs
* fix vcc rawsetjmp
* changing `_longjmp()` to `longjmp()` and
`_setjmp()` to `setjmp()`
* fix
* fix setjmp to clangcl on Windows
* fix genTrySetjmp() to clangcl on Windows
* Windows: enable nimRawSetjmp by default
See #19197. The default setjmp can randomly segfault on windows
* Attempt to disable the flag for bootstraping
* Disable styleCheck for c_setjmp
* move io out of system
* fix tests
* fix tests
* next step
* rename to syncio
* rename
* fix nimscript
* comma
* fix
* fix parts of errors
* good for now
* fix test
* nimRawSetjmp: support Windows
Using `_setjmp()` directly is required to avoid some rare (but very
annoying) exception-related stack corruption leading to segfaults on
Windows, with Mingw-w64 and SEH.
More details: https://github.com/status-im/nimbus-eth2/issues/3121
Also add "nimBuiltinSetjmp" - mostly for benchmarking.
* fix for Apple's Clang++
* adding new system module sysexitprocs and including system exit procedures when registering exit handlers defined in userland
* fixing failing tests and adding initialization guard to handle cases where the module's global init logic isn't invoked first as is the case with some gc implementaions
* js backend shouldn't try to invoke actual system exit procs
* fixing formatting in sysexitprocs.nim
* 256 was too much - my max number of plugins in my engine is 64 and I require two hooks per runtime it looks like with tls emulation turned off, so for my purposes 128 should be sufficient
* so atExit should be enough here, can get rid of all the extra cruft I had added on top since I didn't realize atExit already provided a stack
* done being cute - since newruntime prevents correct cpp codegen for object variants apparently and breaks tests if I try to use std/exitprocs, ddSysExitProc is just going into both modules. Since system doesn't include system/io, polluting system with it doesn't make sense either... at least it is only importc'd when it is required in either module and we don't have to have any weird when defined(nimOwnedEnabled) with a comment explaining why
* deinitializing locks at program exit
* deinitLock shouldn't be called for js backend I guess...
* I suppose this is the best way to detect the
ewruntime option
* I guess I need these guards here too...
* fixing merge conflict
