Building the firmware headers on the host showed two warnings from
machine.h: `typedef struct machine { ... };` and the same for
machine_runtime declare no alias, so the keyword only draws "useless
storage class specifier in empty declaration". Every user says
`struct machine`, so drop the keyword.
-Wno-builtin-declaration-mismatch is a gcc switch and clang reports it
as an unknown option on every build; add it only when the compiler is
not clang.
Compile selected firmware translation units unmodified under host gcc with
AddressSanitizer and UBSan, force-including a shim header that erases the
SDCC 8051 keywords, and link them against a mocked serial ring and console.
A first suite covers the CLI line editor: line entry, backspace editing,
and both long-input overflow cases (length cap and ring-pointer stall).
The only firmware-source change is one #ifndef RTLP_HOST_TEST block in
rtl837x_common.h grouping the libc-named prototypes (sleep/memcpy/memset/
strlen/strcpy/strcmp) so host builds take them from the C library instead;
on-target builds are unaffected.
Run with: make -C test