build: add pytest targets

It enables running pytests in cmake jobs, regardless of underlying build
tool choice (= makes it work with ninja.)

Also:

- drop pytest logic launching `make` and exiting in case of failure.
  Maybe there is a better way and keep this functionality somehow, bind
  it to a command-line option? make it fail softly?

- GHA/linux: invoke pytest via the build, not directly.

- autotools: add missing dummy runtests targets when cross-compiling.

Closes #15034

tests/http/clients/CMakeLists.txt

@@ -22,6 +22,8 @@
 #
 ###########################################################################
 
+add_custom_target(test-http-clients)
+
 # Get 'check_PROGRAMS' variable
 transform_makefile_inc("Makefile.inc" "${CMAKE_CURRENT_BINARY_DIR}/Makefile.inc.cmake")
 include("${CMAKE_CURRENT_BINARY_DIR}/Makefile.inc.cmake")
@@ -30,6 +32,7 @@ foreach(_target IN LISTS check_PROGRAMS)
   set(_target_name "curlt-client-${_target}")
   add_executable(${_target_name} EXCLUDE_FROM_ALL "${_target}.c")
   add_dependencies(testdeps ${_target_name})
+  add_dependencies(test-http-clients ${_target_name})
   target_include_directories(${_target_name} PRIVATE
     "${CURL_BINARY_DIR}/lib"  # for "curl_config.h"
     "${CURL_SOURCE_DIR}/lib"  # for "curl_setup.h"

tests/http/conftest.py

@@ -73,8 +73,6 @@ def env(pytestconfig) -> Env:
         pytest.skip(env.incomplete_reason())
 
     env.setup()
-    if not env.make_clients():
-        pytest.exit(1)
     return env
 
 @pytest.fixture(scope="package", autouse=True)

tests/http/testenv/env.py

@@ -579,12 +579,3 @@ class Env:
                 i = int(fsize / line_length) + 1
                 fd.write(f"{i:09d}-{s}"[0:remain-1] + "\n")
         return fpath
-
-    def make_clients(self):
-        client_dir = os.path.join(self.project_dir, 'tests/http/clients')
-        p = subprocess.run(['make'], capture_output=True, text=True,
-                           cwd=client_dir)
-        if p.returncode != 0:
-            pytest.exit(f"`make`in {client_dir} failed:\n{p.stderr}")
-            return False
-        return True