make gen authors more robust

.mailmap

@@ -13,3 +13,4 @@ csoft2k <csoft2k@hotmail.com>
 Sergio Pulgarin <sergio.pulgarin@gmail.com>
 reck31 <rakesh.gunduka@gmail.com>
 Alex Debiasio <alex.debiasio@thinkin.io>             <alex.debiasio@studenti.unitn.it>
+Maximilian Wagenbach <maximilian.wagenbach@native-instruments.de> <maximilian.wagenbach@native-instruments.de>

doc/generate_authors.sh

@@ -12,7 +12,7 @@ if [ "$#" -eq 1 ]
 	echo "\nNew authorsfile:\n"
 	cat $TEMPAUTHORSFILE
 	echo "\nUsing diff on files...\n"
-        diff -q --from-file $AUTHORSFILE $TEMPAUTHORSFILE
+        diff --suppress-common-lines -b --from-file $AUTHORSFILE $TEMPAUTHORSFILE
     else
 	echo "$GENLIST">$AUTHORSFILE
 fi