Remove trailing whitespace.

Also, the script is a one-liner, stolen from [1]:

ack --print0 -l '[ \t]+$' | xargs -0 -n1 perl -pi -e 's/[ \t]+$//'

[1]
https://stackoverflow.com/questions/149057/how-to-remove-trailing-whitespace-of-all-files-recursively

WPrefs.app/tiff/Makefile.am

@@ -73,5 +73,5 @@ dist_tiffdata_DATA = \
 	windowfocus.tiff \
 	workspace.tiff \
 	workspacename.tiff \
-	xis.tiff 
+	xis.tiff
 endif