Merge bitcoin/bitcoin#24933: util: Replace non-threadsafe strerror

e3a06a3c6c test: Add `strerror` to locale-dependence linter (laanwj)
f00fb1265a util: Increase buffer size to 1024 in SysErrorString (laanwj)
718da302c7 util: Refactor SysErrorString logic (laanwj)
e7f2f77756 util: Use strerror_s for SysErrorString on Windows (laanwj)
46971c6dbf util: Replace non-threadsafe strerror (laanwj)

Pull request description:

  Some uses of non-threadsafe `strerror` have snuck into the code since they were removed in #4152. Add a wrapper `SysErrorString` for thread-safe strerror alternatives (with code from `NetworkErrorString`) and replace all uses of `strerror` with this.

  Edit: I've also added a commit that refactors the code so that buf[] is never read at all if the function fails, making some fragile-looking code unnecessary.

  Edit2: from the linux manpage:
  ```
  ATTRIBUTES
         For an explanation of the terms used in this section, see attributes(7).

         ┌───────────────────┬───────────────┬─────────────────────────┐
         │Interface          │ Attribute     │ Value                   │
         ├───────────────────┼───────────────┼─────────────────────────┤
         │strerror()         │ Thread safety │ MT-Unsafe race:strerror │
         ├───────────────────┼───────────────┼─────────────────────────┤
  …
         ├───────────────────┼───────────────┼─────────────────────────┤
         │strerror_r(),      │ Thread safety │ MT-Safe                 │
         │strerror_l()       │               │                         │
         └───────────────────┴───────────────┴─────────────────────────┘
  ```
  As the function can be called from any thread at any time, using a non-thread-safe function is unacceptable.

ACKs for top commit:
  jonatack:
    ACK e3a06a3c6c

Tree-SHA512: 20e71ebb9e979d4e1d8cafbb2e32e20c2a63f09115fe72cdde67c8f80ae98c531d286f935fd8a6e92a18b72607d7bd3e846b2d871d9691a6036b0676de8aaf25

src/util/system.cpp

@@ -25,6 +25,7 @@
 #include <util/getuniquepath.h>
 #include <util/strencodings.h>
 #include <util/string.h>
+#include <util/syserror.h>
 #include <util/translation.h>
 
 
@@ -1374,7 +1375,7 @@ void ScheduleBatchPriority()
     const static sched_param param{};
     const int rc = pthread_setschedparam(pthread_self(), SCHED_BATCH, &param);
     if (rc != 0) {
-        LogPrintf("Failed to pthread_setschedparam: %s\n", strerror(rc));
+        LogPrintf("Failed to pthread_setschedparam: %s\n", SysErrorString(rc));
     }
 #endif
 }