Adds an optional per-board mac_flash_offset. When non-zero, RTLPlayground
reads a 6-byte MAC from that flash address and uses it if it is a valid
globally-administered unicast address; otherwise it falls back to the
generated locally-administered MAC. Offset 0 (default for every board)
preserves current behaviour.
Enable it for the SWTGW218AS, whose stock firmware keeps the factory MAC
in nvcfg at 0x1FC000. RTLPlayground images and web upgrades only touch
flash below that region, so the factory MAC survives flashing.
Send the configured hostname on discover and request so the DHCP server
can register the device (e.g. in local DNS). Skipped while the hostname
is still empty, i.e. before set_hostname_default() has run.
Honor SOURCE_DATE_EPOCH, falling back to the HEAD commit date and then
to wall-clock when git is absent. Same-commit builds become
byte-identical (BUILD_DATE is baked into the image and covered by the
trailing CRC), which makes it possible to verify that a binary matches
a source tree.
SDCC rejects memset() on the generic &entry pointer (error 78,
incompatible types). The ipmc/l2mc table entries are __xdata; pass an
explicit (__xdata uint8_t *) so the call resolves.
bloqaudio