Build with clang, and the core and store on macOS, again

Apple clang 21 (an M3) and clang 19 refused what gcc let pass (research
029):
- PURE_FIELD_REST was an enum of UINT32_MAX, past an int (C17): a macro.
- a store's publish copied an entry rebuild left unset when the record
  was not found (the copy was never used): copied when it was made.
- the log's image writer kept a count only Linux's sync_file_range uses.
- ",{" + (row == from) read as adding an int to a string: said plainly.
- the tests: mkdtemp, hidden by _POSIX_C_SOURCE on macOS, needs
  _DARWIN_C_SOURCE; a string split so that \x80 and a stay apart is
  bracketed; a count left over and a malloc measure only glibc has.
The core's and the store's tests pass on the Mac.

1 files changed, 1 insertions, 1 deletions

diff --git a/store/store-tree.c b/store/store-tree.c
index ecdced6..3404edd 100644
--- a/store/store-tree.c
+++ b/store/store-tree.c
@@ -1202,7 +1202,7 @@ static PureResult publish(Session *session, Writer *writer, size_t count, const
         written = find(&session->tree, catalog, keys[i], &index, &found, &current, &stored) &&
                   rebuild(&session->tree, catalog, index * RECORD, found ? RECORD : 0,
                           (PureSpan){record, RECORD}, &updated);
-        catalog = updated;
+        if (written) catalog = updated;
     }
     written = written && write_root(&session->tree, writer, &catalog, false) && flush(writer);
     /* Unpublished bytes stay in the tail; the next commit overwrites them. */