He died in 1973, but W.H. Auden is, forgive us, hotter than ever. Last year the British-born poet's ''Funeral Blues'' was part of the eulogy in Four Weddings and a Funeral (prompting a special reprinting from Vintage of ''Funeral'' and nine other poems). Now his ''As I Walked Out One Evening'' makes a cameo in Before Sunrise. Director Richard Linklater admits the inspiration came from Sunrise star Ethan Hawke. ''Ethan knows his poetry,'' says Linklater. So will Auden become the new Kahlil Gibran? The executor of the poet's literary estate, Edward Mendelson, thinks not. ''His songs have a kind of directness and emotional immediacy,'' notes Mendelson, who says the estate was paid ''very little'' for use of the poem. ''But still I was surprised to see a
second (Auden poem) pop up in one year.''