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

scripts/mk-unity.pl

@@ -23,48 +23,91 @@
 #
 ###########################################################################
 
-# Helper script for "unity"-like support in autotools, to generate the umbrella
-# C source that includes the individual source files. Reads Makefile.inc and
-# accepts the variable name containing all the source files to include. Also
-# allow a list of exceptions that are to be excluded from the generated file.
+# Helper script for "unity"-like support in autotools and to bundle up tests
+# for both autotools and cmake. It generates the umbrella C source that
+# includes the individual source files and tests.
 
 use strict;
 use warnings;
 
 if(!@ARGV) {
-    die "Usage: $0 [<c-sources>] [--exclude <exclude-c-sources>]\n";
+    die "Usage: $0 [--test <tests>] [--include <include-c-sources>] [--exclude <exclude-c-sources>] [--srcdir <srcdir>] [--embed]\n";
 }
 
-my $srcdir = shift @ARGV;
-
 # Specific sources to exclude or add as an extra source file
 my @src;
 my %exclude;
+my %include;
 my $in_exclude = 0;
+my $in_include = 0;
+my $srcdir = "";
+my $in_srcdir = 0;
+my $any_test = 0;
+my $embed = 0;
 foreach my $src (@ARGV) {
-    if($in_exclude) {
-        $exclude{$src} = 1;
+    if($src eq "--test") {
+        $in_exclude = 0;
+        $in_include = 0;
     }
     elsif($src eq "--exclude") {
         $in_exclude = 1;
+        $in_include = 0;
+    }
+    elsif($src eq "--include") {
+        $in_exclude = 0;
+        $in_include = 1;
+    }
+    elsif($src eq "--embed") {
+        $embed = 1;
+    }
+    elsif($src eq "--srcdir") {
+        $in_srcdir = 1;
+    }
+    elsif($in_srcdir) {
+        $srcdir = $src;
+        $in_srcdir = 0;
+    }
+    elsif($in_exclude) {
+        $exclude{$src} = 1;
+    }
+    elsif($in_include) {
+        $include{$src} = 1;
+        push @src, $src;
     }
     else {
         push @src, $src;
+        $any_test = 1;
     }
 }
 
-print <<HEADER
-/* !checksrc! disable COPYRIGHT all */
-HEADER
-    ;
+print "/* !checksrc! disable COPYRIGHT all */\n\n";
+if($any_test) {
+    print "#include \"first.h\"\n\n";
+}
+
+my $tlist = "";
 
 foreach my $src (@src) {
-    if($src =~ /\.c$/g && !exists $exclude{$src}) {
-        if(-e "$srcdir/$src") {
-            print "#include \"$srcdir/$src\"\n";
+    if($src =~ /([a-z0-9]+)\.c$/ && !exists $exclude{$src}) {
+        my $name = $1;
+        my $fn = $src;
+        if($srcdir ne "" && (exists $include{$src} || $embed) && -e "$srcdir/$fn") {
+            $fn = $srcdir . "/" . $fn;
+        }
+        if($embed) {
+            my $content = do { local $/; open my $fh, '<', $fn or die $!; <$fh> };
+            print $content;
         }
         else {
-            print "#include \"$src\"\n";
+            print "#include \"$fn\"\n";
+        }
+        if(not exists $include{$src}) {  # register test entry function
+            $tlist .= "  {\"$name\", test_$name},\n";
         }
     }
 }
+
+if($any_test) {
+    print "\nstatic const struct entry_s s_entries[] = {\n$tlist};\n";
+    print "\n#include \"first.c\"\n";
+}