Merge pull request #4076 from Citadel-Station-13/upstream-merge-32858

[MIRROR] Divides species in subtypes, makes viruses able to infect certain subtypes

code/datums/diseases/advance/symptoms/species.dm

@@ -0,0 +1,30 @@
+/datum/symptom/undead_adaptation
+	name = "Necrotic Metabolism"
+	desc = "The virus is able to thrive and act even within dead hosts."
+	stealth = 2
+	resistance = -2
+	stage_speed = 1
+	transmittable = 0
+	level = 5
+	severity = 0
+
+/datum/symptom/undead_adaptation/Start(datum/disease/advance/A)
+	if(!..())
+		return
+	A.process_dead = TRUE
+	A.infectable_hosts |= SPECIES_UNDEAD
+
+/datum/symptom/inorganic_adaptation
+	name = "Inorganic Biology"
+	desc = "The virus can survive and replicate even in an inorganic environment, increasing its resistance and infection rate."
+	stealth = -1
+	resistance = 4
+	stage_speed = -2
+	transmittable = 3
+	level = 5
+	severity = 0
+
+/datum/symptom/inorganic_adaptation/Start(datum/disease/advance/A)
+	if(!..())
+		return
+	A.infectable_hosts |= SPECIES_INORGANIC