fix nim check nimscript [backport: 1.6] (#19444)

fix #19440; fix #3858

compiler/main.nim

@@ -62,6 +62,9 @@ proc commandCheck(graph: ModuleGraph) =
   let conf = graph.config
   conf.setErrorMaxHighMaybe
   defineSymbol(conf.symbols, "nimcheck")
+  if optWasNimscript in conf.globalOptions:
+    defineSymbol(conf.symbols, "nimscript")
+    defineSymbol(conf.symbols, "nimconfig")
   semanticPasses(graph)  # use an empty backend for semantic checking only
   compileProject(graph)
 
@@ -367,7 +370,8 @@ proc mainCommand*(graph: ModuleGraph) =
       msgWriteln(conf, "-- end of list --", {msgStdout, msgSkipHook})
 
       for it in conf.searchPaths: msgWriteln(conf, it.string)
-  of cmdCheck: commandCheck(graph)
+  of cmdCheck:
+    commandCheck(graph)
   of cmdParse:
     wantMainModule(conf)
     discard parseFile(conf.projectMainIdx, cache, conf)