autotools: add support for 'unity' builds, enable in CI

Implement the "unity" builds as known from CMake, but for autotools.
It's limited to `lib` and `src` (CMake also supports it in `t

autotools: add support for 'unity' builds, enable in CI

Implement the "unity" builds as known from CMake, but for autotools.
It's limited to `lib` and `src` (CMake also supports it in `tests`).

Enable with: `--enable-unity` (disabled by default)

Unity builds speed up builds significantly. Cygwin and Windows builds in
particular, but the effect is noticeable on most systems. It also allows
discovering unity issues with autotools, benefitting also CMake when
building the same combination. In CI it makes turnaround times quicker.

This closes build performance with CMake. autotools still lags behind
because it builds shared and static libcurl in two, separate passes.
CMake does it in one. Manpage compilation isn't batched, it is in CMake.
After unity and test bundle support the slowest parts of the build are
the configuration phase (which is effectively a tedious, non-parallel,
compilation and/or linking of 300+ tiny programs. The next bottleneck
is compiling individual examples and finally test servers (only slow
with autotools).

The autotools implementation is slightly less efficient than CMake,
because 3 sources are permanently excluded while in CMake this isn't
necessary and solved more efficiently while building libtests. There is
also no 'unity' support for tests, making them a less efficient also.

Enable it in CI for most `configure` jobs. Except in GHA/dist (though
it works fine there too), to use the default config there. Also skip for
the Linux AWC-LC job where it made builds time a few seconds longer
(reason undiscovered.)

Autotools test suite builds compared between master -> `--enable-unity`:
- GHA/Linux: 32s -> 12s
https://github.com/curl/curl/actions/runs/10705668823/job/29681617374
https://github.com/curl/curl/actions/runs/10742978889/job/29796766297
- GHA/macOS: 37s -> 10s
https://github.com/curl/curl/actions/runs/10705668813/job/29681632885
https://github.com/curl/curl/actions/runs/10742978699/job/29796768875
- GHA/FreeBSD: 15m25 -> 10m58 (full workflow time, ~qemu)
https://github.com/curl/curl/actions/runs/10705668811/job/29681607915
https://github.com/curl/curl/actions/runs/10742978937/job/29796766115
- GHA/Cygwin: 3m32 -> 1m21
https://github.com/curl/curl/actions/runs/10705668809/job/29681609965
https://github.com/curl/curl/actions/runs/10742978645/job/29796756933
- GHA/MSYS2: 2m42 -> 50s
https://github.com/curl/curl/actions/runs/10705668808/job/29681621166
https://github.com/curl/curl/actions/runs/10742978662/job/29799739289
- GHA/mingw-w64: 5m32 -> 1m23
https://github.com/curl/curl/actions/runs/10705668808/job/29681628787
https://github.com/curl/curl/actions/runs/10742978662/job/29799741568

Closes #14815

show more ...

cmake: separate target for examples, optimize CI, fix fallouts

- Move `docs/examples` builds under a separate target.

- Make `BUILD_EXAMPLES` default to `ON`. It means to generate t

cmake: separate target for examples, optimize CI, fix fallouts

- Move `docs/examples` builds under a separate target.

- Make `BUILD_EXAMPLES` default to `ON`. It means to generate the rules
for `docs/examples` by default, but not build them. To build them,
an explicit `make curl-examples` (or ninja, etc) command is necessary.
This syncs behaviour with autotools, and also how both cmake and
autotools are building tests.

- GHA: update cmake jobs to use the new way of building examples.

- GHA: move examples build step at the end of the job, after building
and running tests. This allows to have build and test run results
faster, and leave the seldom-changing examples build to the end.
Building examples is the slowest build step with no practical way to
make them fast.

- appveyor: enable building examples in two old-MSVC jobs.

- examples: fix examples to build cleanly with old MSVC versions.

- GHA/non-native: move example build log under a GHA foldable section.

- GHA/windows: move building examples into separate step for Linux cross
jobs.

Follow-up to dfdd978f7c60224dffe2aac25b436dc0a5cd0186 #13491
Closes #14906

show more ...

CI: move Azure jobs to GHA, fix fallouts, sshserver, runtests tweaks

CI:

- GHA/windows: enable OpenSSH server, SysInternals `handle`, `impacket`.
Skip `impacket` on MSYS2 due

CI: move Azure jobs to GHA, fix fallouts, sshserver, runtests tweaks

CI:

- GHA/windows: enable OpenSSH server, SysInternals `handle`, `impacket`.
Skip `impacket` on MSYS2 due to install failure.
Skip OpenSSH server for old/standalone mingw-w64 (building curl
without SSH there.)
- GHA/windows: make test tool installs a separate step.
- GHA/cygwin: enable OpenSSH server.
Skip `impacket`: it's compiling for 7 minutes then breaks.
Skip `stunnel` due to sluggish test run performance.
(This update is unrelated to Azure jobs.)
- GHA/linux: migrate Linux jobs from Azure CI.
- GHA/linux: migrate scanbuild job from Azure CI.
- GHA/linux: enable libssh2 in a job. Also enable valgrind.
- CI/windows: enable SSPI in two jobs.
- CI/windows: disable zlib in one more job.
- CI/windows: improve `if` condition checking GnuTLS.
- CI/windows: ignore SFTP/SCP tests as necessary.
- universally ignore SCP tests, they fail everywhere.
- ignore test 612.
- ignore test 613 616 618 with MSYS2 mingw-w64.
- ignore test 614 with libssh.
- ignore all SFTP with MSYS2 native.
- ignore all SFTP with vcpkg with `libssh2[core,zlib]`.
- ignore a couple of SFTP tests with MSYS2 mingw-w64.
(This matches settings on Azure CI.)
- GHA/windows: ignore failing 1451 'Basic SMB request' test for
old mingw-w64 7.3.0 (but not for 9.5.0!):
```
2024-09-11 21:45:59,738 ERROR smbComNegotiate: b'NT LM 0.12\x00' is not in list
[...]
curl: (7) Could not connect to server
[...]
FAIL 1451: 'Basic SMB request' SMB
```
Ref: https://github.com/curl/curl/actions/runs/10816280746/job/30007130770#step:13:3546
- CI/Azure: delete, now moved to GHA.

sshserver:

- sshserver: fix permissions for SSH host key on Windows, allowing sshd
to launch.
- sshserver: fix initializing config paths with Cygwin/MSYS2 sshd.
- sshserver: fix initializing config paths in parallel builds.
- sshserver: delete redundant `DenyUsers`. This also opens the way
to allow multiple usernames.
- sshserver: fix `AllowUsers` for GHA/windows, by allowing the
domainless username again.
Follow-up to 3ee7c676ec8ef32e3a9cb4d0fb2929a8335d58db #5721
- sshserver: fix `Deprecated option` warnings in `sshd_config`:
```
D:/a/curl/curl/bld/tests/log/2/server/curl_sshd_config line 7: Deprecated option AuthorizedKeysFile2
D:/a/curl/curl/bld/tests/log/2/server/curl_sshd_config line 25: Deprecated option KeyRegenerationInterval
D:/a/curl/curl/bld/tests/log/2/server/curl_sshd_config line 35: Deprecated option RhostsRSAAuthentication
D:/a/curl/curl/bld/tests/log/2/server/curl_sshd_config line 36: Deprecated option RSAAuthentication
D:/a/curl/curl/bld/tests/log/2/server/curl_sshd_config line 37: Deprecated option ServerKeyBits
D:/a/curl/curl/bld/tests/log/2/server/curl_sshd_config line 41: Deprecated option UseLogin
```
- sshserver: fix `Deprecated option` warnings in `ssh_config` with
Cygwin/MSYS2.
- sshserver: fix dumping config files due to the filenames missing their
full paths.
- sshserver: add workaround to make `logmsg` messages visible.
Before this patch they only went to a file and never shown.

runtests:

- runtests: log details when these Windows commands are called:
`handle`, `taskkill`, `tasklist`.
- runtests: add documentation links to Windows tools:
`handle`, `taskkill`, `tasklist`, `icacls`.
- runtests: add `-t` (kill whole tree) option to `taskkill` in
`servers.pm`, syncing it with the other `taskkill` call.
Follow-up to bc72a78a11764558639131d51fa8e7c81ee1e113 #14488
- runtests: show warning if Sysinternals `handle` tool is missing.
- runtests: drop Windows XP Home compatibility `tskill` call.
The call was made on all Windows versions. It's possibly overkill to
do this, because XP Home is probably rarely used for running curl
tests these days. In case it's needed, it'd be better to put it under
an explicit option.
- runtests: show Perl version and path.

Fix/silence fallouts:

- unit2603: fix building with disabled HTTP support.
- unit2604: silence `-Woverlength-strings` warnings in C89 mode.
- test437, test1614: fix to pass with no-IPv6 builds.

Closes #14859

show more ...

GHA: replace make with ninja in Cygwin, MSYS2 and mingw-w64 cmake jobs

Speed-ups:
- cygwin build: 47s -> 29s
- cygwin build tests: 3m12 -> 2m32
- MSYS2 native build: 29s -> 16s

GHA: replace make with ninja in Cygwin, MSYS2 and mingw-w64 cmake jobs

Speed-ups:
- cygwin build: 47s -> 29s
- cygwin build tests: 3m12 -> 2m32
- MSYS2 native build: 29s -> 16s
- MSYS2 native build tests: 2m24 -> 1m52
- MSYS2/mingw-w64: already had ninja installed and used implicitly.
- linux-mingw-w64-cross: 31s -> 25s

before:
cygwin: https://github.com/curl/curl/actions/runs/10866939355/job/30155134299
windows: https://github.com/curl/curl/actions/runs/10866939361

after:
cygwin: https://github.com/curl/curl/actions/runs/10867861215/job/30157121784
windows: https://github.com/curl/curl/actions/runs/10867861208?pr=14914

Closes #14914

show more ...

CI: add test timeouts, more cmake build tests, fix VS2010 C warning

- GHA/macos: set timeout for test runs.
Double the value for autotools to fit torture tests.
- GHA/cygwin: reduc

CI: add test timeouts, more cmake build tests, fix VS2010 C warning

- GHA/macos: set timeout for test runs.
Double the value for autotools to fit torture tests.
- GHA/cygwin: reduce test run timeout for autotools.
- GHA/cygwin: enable building tests with cmake.
- GHA/windows: enable building tests with MSYS cmake.
- GHA/windows: enable building tests with MSVC UWP.
- appveyor: enable building tests with VS2008 x86 and VS2010 x64.
- tests: add workaround compiler warnings when building with VS2010:
```
tests\server\util.c(482): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
tests\server\util.c(486): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
tests\server\util.c(490): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
tests\server\util.c(720): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
tests\server\util.c(726): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
tests\server\util.c(732): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
tests\server\util.c(781): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
tests\server\util.c(785): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
tests\server\util.c(789): warning C4306: 'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' of greater size
```
Ref: https://ci.appveyor.com/project/curlorg/curl/builds/50485633/job/4ujlwxod3cexmn2q#L1535

With this, tests are built in all GHA cygwin/windows jobs.

Timeouts avoid long runs with runaway issues, example:
https://github.com/curl/curl/actions/runs/10575522173

Closes #14700

show more ...

GHA: add yamlcheck

Uses `yamllint`.

Also:
- fix warning for existing YAML files:
```
[truthy] truthy value should be one of [false, true]
```

Closes #

GHA: add yamlcheck

Uses `yamllint`.

Also:
- fix warning for existing YAML files:
```
[truthy] truthy value should be one of [false, true]
```

Closes #14650

show more ...

GHA/windows: move Cygwin into its own workflow

Cygwin runs stable but slow, while native Windows in the same workflow
runs fast but unreliable (hangs). GHA requires all jobs to finish be

GHA/windows: move Cygwin into its own workflow

Cygwin runs stable but slow, while native Windows in the same workflow
runs fast but unreliable (hangs). GHA requires all jobs to finish before
allowing to re-run failed ones. Before this patch this meant waiting for
the slow Cygwin jobs to re-run hung native jobs. After this patch Cygwin
jobs run in their own workflow, allowing to re-run broken Windows jobs
earlier.

Follow-up to 0d125287296857fc4a931a0c20d0ffcb1f731807 #14236
Closes #14366

show more ...