The dead-branch pruner marked any assumed-live branch as 'taken', so the
#else of an UNKNOWN condition was skipped. GxEPD2 guards its GFX base
class with '#if ENABLE_GxEPD2_GFX (default 0) ... #else #include
<Adafruit_GFX.h>' — the pruned #else silently dropped the Adafruit_GFX
dependency and every GxEPD2 e-paper example failed with 'fatal error:
Adafruit_GFX.h: No such file'. Found by the nightly gallery compile smoke.
'taken' is now set only by PROVABLY-true conditions (all identifiers in
the known-true set), keeping the 2026-08-03 ESPAsyncWebServer behaviour:
provably-dead branches still prune, provably-true branches still kill
their #else.