Fix silly G++ warning.
Fix silly G++ warning.

LebedevRI/rawspeed,LebedevRI/rawspeed,mgehre/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,mgehre/rawspeed,klauspost/rawspeed,darktable-org/rawspeed,anarsoul/rawspeed,LebedevRI/rawspeed,klauspost/rawspeed,LebedevRI/rawspeed,anarsoul/rawspeed,anarsoul/rawspeed