refactoring: explict config state instead of globals

compiler/modulegraphs.nim

@@ -25,7 +25,7 @@
 ## - Its dependent module stays the same.
 ##
 
-import ast, intsets, tables
+import ast, intsets, tables, options
 
 type
   ModuleGraph* = ref object
@@ -39,16 +39,18 @@ type
     importStack*: seq[int32]  # The current import stack. Used for detecting recursive
                               # module dependencies.
     backend*: RootRef # minor hack so that a backend can extend this easily
+    config*: ConfigRef
 
 {.this: g.}
 
-proc newModuleGraph*(): ModuleGraph =
+proc newModuleGraph*(config: ConfigRef = nil): ModuleGraph =
   result = ModuleGraph()
   initStrTable(result.packageSyms)
   result.deps = initIntSet()
   result.modules = @[]
   result.importStack = @[]
   result.inclToMod = initTable[int32, int32]()
+  result.config = config
 
 proc resetAllModules*(g: ModuleGraph) =
   initStrTable(packageSyms)