Before this patch the signal handler called `logmsg()` which in turn
called `printf()` variants (internal implementations), and `FILE *`
functions, `localtime()`. Some of these called `malloc`/`free`, which
isn't supported in s signal handler. Replace them with `write` calls,
losing some logging functionality.

Also:
- De-dupe and move `STD*_FILENO` macros to `lib/curl_setup.h`. Revert
  the `src` definition to point to `stderr`, instead of `tool_stderr`.
  Follow-up to e5bb88b curl#11958

POSIX specs with list of functions allowed in a signal handler:
2004: https://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html#tag_02_04_03
2017: https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04_03
2024: https://pubs.opengroup.org/onlinepubs/9799919799/functions/V2_chap02.html#tag_16_04_03

Linux CI run with the thread sanitizer going crazy when
hitting the signal handler in test 1238 and 1242 (TFTP):
```
WARNING: ThreadSanitizer: signal-unsafe call inside of a signal (pid=12582)
    #0 malloc <null> (servers+0x5ed70)
    #1 _IO_file_doallocate <null> (libc.so.6+0x851b4)
    curl#2 formatf /home/runner/work/curl/curl/bld/tests/server/../../lib/../../lib/mprintf.c:886:9 (servers+0xdff77)
[...]
WARNING: ThreadSanitizer: signal-unsafe call inside of a signal (pid=12582)
    #0 free <null> (servers+0x5f453)
    #1 fclose <null> (libc.so.6+0x8532f)
    curl#2 logmsg /home/runner/work/curl/curl/bld/tests/server/../../../tests/server/util.c:134:5 (servers+0xe684d)
```
Ref: https://github.com/curl/curl/actions/runs/14118903372/job/39555309490?pr=16851

Closes curl#16852

Replace autotools with cmake to avoid libtool wrappers that are changing
`LD_LIBRARY_PATH` in a way incompatible with the thread sanitizer.

To fix the output when the sanitizier is finding something:
```
==51718==WARNING: Can't write to symbolizer at fd 7
 /usr/bin/llvm-symbolizer-18: /home/runner/work/curl/curl/bld/lib/.libs/libcurl.so.4: no version information available (required by /usr/bin/llvm-symbolizer-18)
 /usr/bin/llvm-symbolizer-18: symbol lookup error: /home/runner/openssl/lib/libcrypto.so.3: undefined symbol: __tsan_func_entry
```
Ref: https://github.com/curl/curl/actions/runs/16911402500/job/47913783729#step:39:4466

After:
```
 13:50:04.117885 == Info:ThreadSanitizer: thread T1  finished with ignores enabled, created at:
  closing connection #0
     #0 pthread_create <null> (libtests+0x6bc0f) (BuildId: 4fe889446291259934205ac03931c397aa0210d3)
     #1 Curl_thread_create /home/runner/work/curl/curl/lib/curl_threads.c:73:6 (libcurl.so.4+0x55a76) (BuildId: cb0f14ba2ad68c9cab0c980d9a5d7a53cc0782da)
     curl#2 async_thrdd_init /home/runner/work/curl/curl/lib/asyn-thrdd.c:500:26 (libcurl.so.4+0x1c153) (BuildId: cb0f14ba2ad68c9cab0c980d9a5d7a53cc0782da)
[...]
```
Ref: https://github.com/curl/curl/actions/runs/16939193922/job/48003405272?pr=18274#step:39:4018

Also:
- disable memory tracker which turned out to be incompatible with
  the thread sanitizer and detaching threads.
  Ref: curl#18263 and #curl IRC.
- the job is ~30 seconds faster after this patch.

Reported-by: Stefan Eissing
Bug: curl#18263 (comment)
Follow-up to a2bcec0 curl#14751
Closes curl#18274