pass platform argument only if vccexe is used (#13078)

* pass platform only if vccexe is used * fixes #12297

Author: cooldome

compiler/extccomp.nim

@@ -558,15 +558,14 @@ proc getCompileOptions(conf: ConfigRef): string =
 proc vccplatform(conf: ConfigRef): string =
  # VCC specific but preferable over the config hacks people
  # had to do before, see #11306
- case conf.target.targetCPU
- of cpuI386:
- result = " --platform:x86"
- of cpuArm:
- result = " --platform:arm"
- of cpuAmd64:
- result = " --platform:amd64"
- else:
- result = ""
+ if conf.cCompiler == ccVcc: 
+ let exe = getConfigVar(conf, conf.cCompiler, ".exe")
+ if "vccexe.exe" == extractFilename(exe):
+ result = case conf.target.targetCPU
+ of cpuI386: " --platform:x86"
+ of cpuArm: " --platform:arm"
+ of cpuAmd64: " --platform:amd64"
+ else: ""
 
 proc getLinkOptions(conf: ConfigRef): string =
  result = conf.linkOptions & " " & conf.linkOptionsCmd & " "
@@ -596,7 +595,7 @@ proc getLinkerExe(conf: ConfigRef; compiler: TSystemCC): string =
 
 proc getCompileCFileCmd*(conf: ConfigRef; cfile: Cfile,
  isMainFile = false; produceOutput = false): string =
- var c = conf.cCompiler
+ let c = conf.cCompiler
  # We produce files like module.nim.cpp, so the absolute Nim filename is not
  # cfile.name but `cfile.cname.changeFileExt("")`:
  var options = cFileSpecificOptions(conf, cfile.nimname, cfile.cname.changeFileExt("").string)