Appoggiatura slur not crossing beam

[Urs Liska]

In an appoggiatura with the main note having the stem downwards the 
appoggiatura's slur will cross the stem, see the first of the two 
instances in this example:

{
  \appoggiatura d''4 c''
  \appoggiatura d'4 c'
}

A client requests me to shorten the slurs so not to cross the stem. Is 
there a more convenient and consistent solution to this short of 
\shape-ing each slur individually?

Thanks
Urs

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