Portability Warning Options:
  backslash [no]: Backslash in standard-conforming strings
  common-alignment [no]: COMMON not in descending size order
  hollerith [no]: Hollerith constants (except in FORMAT)
  long-string [no]: Strings over 255 chars long
  mixed-equivalence [yes]: Different data types equivalenced
  mixed-size [yes]: Default and explicit size types mixed
  real-do [no]: Non-integer DO loops
  param-implicit-type [no]: Implicit type of PARAMETER differs from default type
  tab [no]: Tabs in source code
Prefix option name with no- to turn off option
If no options given, equivalent to -portability=all
Special keywords:
  help: Print this list
  all: Set all options
  none: Clear all options