End 512 compiler support for good (#8951)

code/__defines/lists.dm

@@ -16,10 +16,6 @@
 #define safepick(L) LAZYPICK(L,null)
 #define listgetindex(L,I) LAZYACCESS(L,I)
 
-#if DM_VERSION < 513
-#define islist(L) istype(L,/list)
-#endif
-
 // binary search sorted insert
 // IN: Object to be inserted
 // LIST: List to insert object into

code/__defines/misc.dm

@@ -291,17 +291,8 @@
 #define NL_PERMANENT_DISABLE 2
 
 // Used for creating soft references to objects. A manner of storing an item reference
-// as text so you don't necessarily fuck with an object's ability to be garbage collected.
-#if DM_VERSION < 513
-
-#define SOFTREF(A) "\ref[A]"
-
-#else
-
 #define SOFTREF(A) ref(A)
 
-#endif
-
 // This only works on 511 because it relies on 511's `var/something = foo = bar` syntax.
 #define WEAKREF(D) (istype(D, /datum) && !D:gcDestroyed ? (D:weakref || (D:weakref = new/datum/weakref(D))) : null)
 

code/_helpers/unsorted.dm

@@ -556,12 +556,6 @@ Turf and target are seperate in case you want to teleport some distance from a t
 /proc/between(var/low, var/middle, var/high)
 	return max(min(middle, high), low)
 
-#if DM_VERSION < 513
-proc/arctan(x)
-	var/y=arcsin(x/sqrt(1+x*x))
-	return y
-#endif
-
 //returns random gauss number
 proc/GaussRand(var/sigma)
   var/x,y,rsq

code/global.dm

@@ -1,6 +1,6 @@
 //#define TESTING
-#if DM_VERSION < 512
-#error Your version of BYOND is too old to compile the code. At least BYOND 512 is required.
+#if DM_VERSION < 513
+#error Your version of BYOND is too old to compile the code. At least BYOND 513 is required.
 #endif