Usage Warning Options:
  arg-alias [yes]: scalar argument same as another is modified
  arg-array-alias [yes]: argument in same array as another is modified
  arg-common-alias [yes]: scalar argument same as common variable, either is modified
  arg-common-array-alias [yes]: array argument same as common variable, either is modified
  arg-const-modified [yes]: constant or expression argument is modified
  arg-unused [yes]: dummy argument declared but not used
  com-block-unused [yes]: whole common block declared but not used
  com-block-volatile [yes]: common block may lose definition if volatile
  com-var-set-unused [yes]: common variable set but not used
  com-var-uninitialized [yes]: common variable used but not set
  com-var-unused [yes]: common variable declared but not used
  do-index-modified [yes]: active DO index variable modified
  ext-multiply-defined [yes]: external multiply defined
  ext-declared-only [yes]: name declared EXTERNAL but not defined or used
  ext-undefined [yes]: external declared or used but not defined (= -external)
  ext-unused [yes]: external defined but not used
  label-undefined [yes]: label used but undefined
  label-unused [yes]: label defined but unused
  var-set-unused [no]: local variable set but not used
  var-uninitialized [no]: local variable used before set
  var-unused [no]: local variable declared but not used
Prefix option name with no- to turn off option
If no options given, equivalent to -usage=all
Special keywords:
  help: Print this list
  all: Set all options
  none: Clear all options