libsql-sqlite3: Sync ext/misc/fileio.c symlink fixes from 3.46.1

The 3.46.1 merge updated shell8.test (adding the symlink extraction
tests shell8-3.x) and the bundled MultipleCiphers fileio.c, but left
libsql-sqlite3/ext/misc/fileio.c at 3.44.0. That file is embedded into
the CLI shell via 'INCLUDE ../ext/misc/fileio.c', so '.ar -x' ran the
stale writeFile() and the new tests failed with
'failed to create symlink: link1'.

Bring writeFile() in line with upstream 3.46.1:

  - Skip utimes() on symbolic links. utimes() follows the link to its
    target; the archive only contains link1 -> file1 (no file1), so the
    dangling link made utimes() fail and broke the first extraction
    (shell8-3.2).
  - unlink(zFile) before symlink() so re-extraction does not fail with
    EEXIST (shell8-3.3).

Author: penberg

libsql-sqlite3/ext/misc/fileio.c

@@ -372,7 +372,9 @@ static int writeFile(
 #if !defined(_WIN32) && !defined(WIN32)
   if( S_ISLNK(mode) ){
     const char *zTo = (const char*)sqlite3_value_text(pData);
-    if( zTo==0 || symlink(zTo, zFile)<0 ) return 1;
+    if( zTo==0 ) return 1;
+    unlink(zFile);
+    if( symlink(zTo, zFile)<0 ) return 1;
   }else
 #endif
   {
@@ -458,13 +460,19 @@ static int writeFile(
       return 1;
     }
 #else
-    /* Legacy unix */
-    struct timeval times[2];
-    times[0].tv_usec = times[1].tv_usec = 0;
-    times[0].tv_sec = time(0);
-    times[1].tv_sec = mtime;
-    if( utimes(zFile, times) ){
-      return 1;
+    /* Legacy unix.
+    **
+    ** Do not use utimes() on a symbolic link - it sees through the link and
+    ** modifies the timestamps on the target. Or fails if the target does
+    ** not exist.  */
+    if( 0==S_ISLNK(mode) ){
+      struct timeval times[2];
+      times[0].tv_usec = times[1].tv_usec = 0;
+      times[0].tv_sec = time(0);
+      times[1].tv_sec = mtime;
+      if( utimes(zFile, times) ){
+        return 1;
+      }
     }
 #endif
   }