tests: always make bundles, adapt build and tests

Make test bundles the default. Drop non-bundle build mode.
Also do all the optimizations and tidy-ups this allows, simpler builds,
less bundle exceptions, streamlined build mechanics.

Also rework the init/deinit macro magic for unit tests. The new method
allows using unique init/deinit function names, and calling them with
arguments. This is in turn makes it possible to reduce the use of global
variables.

Note this drop existing build options `-DCURL_TEST_BUNDLES=` from cmake
and `--enable-test-bundles` / `--disable-test-bundles` from autotools.

Also:
- rename test entry functions to have unique names: `test_<testname>`
  This removes the last exception that was handled in the generator.
- fix `make dist` to not miss test sources with test bundles enabled.
- sync and merge `tests/mk-bundle.pl` into `scripts/mk-unity.pl`.
- mk-unity.pl: add `--embed` option and use it when `CURL_CLANG_TIDY=ON`
  to ensure that `clang-tidy` does not miss external test C sources.
  (because `clang-tidy` ignores code that's #included.)
- tests/unit: drop no-op setup/stop functions.
- tests: reduce symbol scopes, global macros, other fixes and tidy-ups.
- tool1621: fix to run, also fix it to pass.
- sockfilt: fix Windows compiler warning in certain unity include order,
  by explicitly including `warnless.h`.

Follow-up to 6897aeb105 #17468

Closes #17590

tests/server/Makefile.am

@@ -40,11 +40,16 @@ AM_CPPFLAGS = -I$(top_srcdir)/include        \
               -I$(top_srcdir)/src            \
               -I$(top_srcdir)/tests/server
 
-# Prevent LIBS from being used for all link targets
-LIBS = $(BLANK_AT_MAKETIME)
+# Get BUNDLE, BUNDLE_SRC, FIRSTFILES, UTILS, MEMDEBUG, CURLX_SRCS, TESTFILES variables
+include Makefile.inc
+
+EXTRA_DIST = CMakeLists.txt .checksrc $(FIRSTFILES) $(UTILS) $(TESTFILES)
 
 CFLAGS += @CURL_CFLAG_EXTRAS@
 
+# Prevent LIBS from being used for all link targets
+LIBS = $(BLANK_AT_MAKETIME)
+
 if DOING_NATIVE_WINDOWS
 AM_CPPFLAGS += -DCURL_STATICLIB
 endif
@@ -57,32 +62,23 @@ AM_CPPFLAGS += -DCURLDEBUG
 endif
 endif
 
-AM_CPPFLAGS += -DWITHOUT_LIBCURL
+AM_CPPFLAGS += -DWITHOUT_LIBCURL -DCURL_NO_OLDIES
 
-# Makefile.inc provides neat definitions
-include Makefile.inc
-
-EXTRA_DIST = CMakeLists.txt .checksrc mk-bundle.pl $(FIRSTFILES)
-
-if USE_TEST_BUNDLES
-server_EXCLUDE =
+bundle_EXCLUDE =
 if ENABLE_SERVER_DEBUG
 if CURLDEBUG
-server_EXCLUDE += $(MEMDEBUG)
+bundle_EXCLUDE += $(MEMDEBUG)
 endif
 endif
-server_bundle.c: $(top_srcdir)/tests/server/mk-bundle.pl $(MEMDEBUG) $(CURLX_SRCS) $(USEFUL) $(INET_PTON) $(UTIL) $(FIRSTFILES)
-	@PERL@ $(top_srcdir)/tests/server/mk-bundle.pl $(MEMDEBUG) $(CURLX_SRCS) $(USEFUL) $(INET_PTON) $(UTIL) $(SERVERPROGS) --exclude $(server_EXCLUDE) > server_bundle.c
+$(BUNDLE_SRC): $(top_srcdir)/scripts/mk-unity.pl Makefile.inc $(FIRSTFILES) $(UTILS) $(MEMDEBUG) $(CURLX_SRCS) $(TESTFILES)
+	@PERL@ $(top_srcdir)/scripts/mk-unity.pl --include $(UTILS) $(MEMDEBUG) $(CURLX_SRCS) --test $(TESTFILES) --exclude $(bundle_EXCLUDE) > $(BUNDLE_SRC)
 
-noinst_PROGRAMS = servers
-nodist_servers_SOURCES = server_bundle.c
-servers_SOURCES = $(server_EXCLUDE)
+noinst_PROGRAMS = $(BUNDLE)
+nodist_servers_SOURCES = $(BUNDLE_SRC)
+servers_SOURCES = $(bundle_EXCLUDE)
 servers_LDADD = @CURL_NETWORK_AND_TIME_LIBS@
 servers_CFLAGS = $(AM_CFLAGS)
-CLEANFILES = server_bundle.c
-else
-noinst_PROGRAMS = $(SERVERPROGS)
-endif
+CLEANFILES = $(BUNDLE_SRC)
 
 CHECKSRC = $(CS_$(V))
 CS_0 = @echo "  RUN     " $@;
@@ -92,9 +88,12 @@ CS_ = $(CS_0)
 # ignore generated C files since they play by slightly different rules!
 checksrc:
 	$(CHECKSRC)(@PERL@ $(top_srcdir)/scripts/checksrc.pl -D$(srcdir) \
-	  -W$(srcdir)/server_bundle.c \
+	  -W$(srcdir)/$(BUNDLE_SRC) \
 	  $(srcdir)/*.[ch])
 
 if NOT_CURL_CI
 all-local: checksrc
 endif
+
+clean-local:
+	rm -f $(BUNDLE)