message: cxx: Fix bogus when injecting -all_load option.
diff: @@ -881,7 +881,7 @@ class GccToolkit(Toolkit):
  self.__libraries_flags(cfg, libraries, cmd)
  if cfg.whole_archive:
  if self.os is drake.os.macos:
  - cmd += '-Wl,-all_load' # close enough
  + cmd.append( '-Wl,-all_load') # close enough
  else:
  pre=list()
  ar=list()
  @@ -929,7 +929,7 @@ class GccToolkit(Toolkit):
  self.__libraries_flags(cfg, to_link, cmd)
  if cfg.whole_archive:
  if self.os is drake.os.macos:
  - cmd += '-Wl,-all_load' # close enough
  + cmd.append('-Wl,-all_load') # close enough
  else:
  pre=list()
  ar=list()
  