declaration_settles tested the exact-case name before the slot, so on a
filesystem that folds case a declaration spelled otherwise never settled
the core's file: RetroBat's 32X_G_BIOS.BIN left BlastEm's 32X_G_BIOS.bin
undeclared, and verify counted ten such entries as core files. A slot a
case-insensitive platform fills now settles the entry whatever the
spelling (case_folded_slots), the slot arbitration judging its bytes as
for the exact name. Lakka and RetroPie, which keep both names, are
unchanged. Measured: 10 entries settle on RetroBat, 21 on RetroArch.
generate_site.py builds its gap report through cross_reference() without
the folded slots; it needs folded_declared_slots() passed in the same way
as the command line now does.
The gap report took a file's libretro path even where the platform
runs the standalone build, so it named Cemu/keys.txt for Batocera
while verify named keys.txt, and settled the declaration on a slot
the platform never fills. Both now read standalone_path there.