introduce --symbolFiles:v2 as the next attempt to bring symbol files to Nim

compiler/commands.nim

@@ -603,6 +603,7 @@ proc processSwitch(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
     of "off": gSymbolFiles = disabledSf
     of "writeonly": gSymbolFiles = writeOnlySf
     of "readonly": gSymbolFiles = readOnlySf
+    of "v2": gSymbolFiles = v2Sf
     else: localError(info, errOnOrOffExpectedButXFound, arg)
   of "skipcfg":
     expectNoArg(switch, arg, pass, info)

compiler/options.nim

@@ -148,7 +148,7 @@ var
 
 type
   SymbolFilesOption* = enum
-    disabledSf, enabledSf, writeOnlySf, readOnlySf
+    disabledSf, enabledSf, writeOnlySf, readOnlySf, v2Sf
 
 var gSymbolFiles*: SymbolFilesOption