remove more global variables in the Nim compiler

compiler/vmmarshal.nim

@@ -10,7 +10,7 @@
 ## Implements marshaling for the VM.
 
 import streams, json, intsets, tables, ast, astalgo, idents, types, msgs,
-  options
+  options, lineinfos
 
 proc ptrToInt(x: PNode): int {.inline.} =
   result = cast[int](x) # don't skip alignment