dsub.c: Fix format string type mismatch in database error messages

[justwheel]

Summary

Three fprintf calls in dsub.c use %d to format long int values, producing undefined behavior on 64-bit platforms.

Background

The CI pipeline introduced in PR #38 revealed three -Wformat warnings from both GCC and Clang when compiling dsub.c.
The function rspsb2nl_ declares x as long (line 67) and iloc is assigned from ftell() which returns long (line 111), but the error-reporting fprintf calls on lines 84, 96, and 114 all use %d (which expects int).
On 64-bit platforms where long is 8 bytes and int is 4 bytes, this is undefined behavior per the C standard and could print garbled values in database error messages.

Details

1. dsub.c:84 — fprintf(stderr, "Error seeking database loc %d\n", x); — x is long
2. dsub.c:96 — fprintf(stderr, "Error reading database loc %d\n", x); — x is long
3. dsub.c:114 — fprintf(stderr, "Error seeking database loc %d\n", iloc); — iloc is long (from ftell())

Fix: change %d to %ld in all three calls.
This does not alter game logic — it only corrects the format specifiers in error-handling code paths.

This can be fixed as part of v1.1.0, but will most likely be addressed in a future release to help get recent changes submitted downstream in the Fedora package.

Outcome

The codebase compiles without -Wformat warnings and database error messages display correct seek/read positions on all platforms.