Nimscript: added support for 'patchFile'

compiler/scriptconfig.nim

@@ -13,7 +13,7 @@
 import
   ast, modules, passes, passaux, condsyms,
   options, nimconf, lists, sem, semdata, llstream, vm, vmdef, commands, msgs,
-  os, times, osproc, wordrecg
+  os, times, osproc, wordrecg, strtabs
 
 # we support 'cmpIgnoreStyle' natively for efficiency:
 from strutils import cmpIgnoreStyle
@@ -122,6 +122,12 @@ proc setupVM*(module: PSym; scriptName: string): PEvalContext =
   cbconf warningImpl:
     processSpecificNote(a.getString 0, wWarning, passPP, unknownLineInfo(),
       a.getString 1)
+  cbconf patchFile:
+    let key = a.getString(0) & "_" & a.getString(1)
+    var val = a.getString(2).addFileExt(NimExt)
+    if not isAbsolute(val):
+      val = vthisDir / val
+    gModuleOverrides[key] = val
 
 proc runNimScript*(scriptName: string; freshDefines=true) =
   passes.gIncludeFile = includeModule