tests: build non-debug unit tests with autotools, run them

[vszakats]

Before this patch, autotools disabled building unit tests for
non-debug-enabled (DEBUGBUILD) builds. runtests skipped running this
combination, though they were built in cmake builds. There seems to be
no technical reason anymore for these restrictions. This patch removes
them, allowing to build and run unit tests for non-debug-enabled builds.

To improve unit test build and run coverage.

• autotools: do not disable building unit tests for non-debug-enabled
  build. Bringing behavior closer to cmake builds. (There are still
  exceptions in autotools, something for another PR)

• runtests: run unit tests for non-debug-enabled builds.
  It extends coverage by 50 tests.

• lib/altsvc.c: fix to include CURL_TIME support in libcurlu, for
  unit tests. It fixes test 1654, and syncs CURL_TIME behavior with
  test 1660 and lib/hsts.c.

Ref: 10a7d05
Ref: fc8e0de #13694
Ref: 99f78cb #16770

[vszakats]

This costs build time. It's +50 programs (in bundle mode it's just +1).

Another take on this is to disable building unittests in cmake non-debug-enabled builds.

There is no technical reason not to build them, but if running tests in this combination doesn't make any sense, it'd be best to skip building it also in cmake to save time.

Example with Cygwin, bundles enabled:

• Before: https://github.com/curl/curl/actions/runs/13958126454/job/39074001173
• After: https://github.com/curl/curl/actions/runs/13958975516/job/39078910859?pr=16771

edit: from a test coverage POV building these is pointless, because runtests skips unittest if the build is not debug-enabled. From a build coverage POV, dropping unittests reduces it by disabling unittests in non-debug-enabled cmake jobs, like macos clang-tidy, mingw UWP, mingw32ce, MS-DOS, AmigaOS, and more. Building everything in debug mode would fix it, but that reduces coverage for non-debug builds. Perhaps an extra option to enable building it anyway would solve this. Or, just leaving it as-is and accept that cmake is different here than autotools. The cost of building is much less with cmake, esp when using unity and/or bundles.

[vszakats]

Hm, it looks like unittests do not actually require a debug-enabled build, at least according to a CI run with this runtests condition removed.

Except test 1654 that missed the Debug feature label, and another one that also uses CURL_TIME, without requiring Debug, though that one passed anyway. After fixing 1654, CI is green. Historically this condition may have been related to the entangled UNITTESTS, DEBUGBUILD, CURLDEBUG flag use, but that has been fixed earlier in fc8e0de #13694.

I'd go with unlocking this combination in ./configure, letting unittests build there for non-debug-enabled builds (like with CMake), and also let them run to make the built binaries useful. It also means that unittest are now run in cmake non-debug-enabled builds too, which looks like a useful thing for test coverage (+50 tests):

Before:

TESTINFO: "curl lacks unittest support" 53 times (1300, 1302, 1303, 1304, 1305, 1306, 1308, 1309, 1323 and 44 more)
[...]
TESTDONE: 1525 tests out of 1525 reported OK: 100%

https://github.com/curl/curl/actions/runs/13967157858/job/39100108697#step:15:3552

After:

TESTDONE: 1574 tests out of 1574 reported OK: 100%

https://github.com/curl/curl/actions/runs/13969017959/job/39106067593?pr=16771