Fix compilation problem when TIFF dependency is missing.
Fix compilation problem when TIFF dependency is missing.

cha007/vigra,timoMa/vigra,capturePointer/vigra,capturePointer/vigra,dagophil/vigra,dagophil/vigra,mmuellner/vigra,stuarteberg/vigra,stuarteberg/vigra,DaveRichmond-/vigra,hmeine/vigra,DaveRichmond-/vigra,xiwei-zhang/vigra,cbecker/vigra,mmuellner/vigra,dstoe/vigra,xiwei-zhang/vigra,kod3r/vigra,timoMa/vigra,mmuellner/vigra,psteinb/vigra,stuarteberg/vigra,cha007/vigra,capturePointer/vigra,martinsch/vigra,psteinb/vigra,psteinb/vigra,capturePointer/vigra,dstoe/vigra,dstoe/vigra,DaveRichmond-/vigra,funkey/vigra,funkey/vigra,cbecker/vigra,dstoe/vigra,ThomasWalter/vigra,DaveRichmond-/vigra,xiwei-zhang/vigra,ThomasWalter/vigra,ThomasWalter/vigra,dagophil/vigra,martinsch/vigra,martinsch/vigra,dagophil/vigra,kod3r/vigra,kod3r/vigra,hmeine/vigra,xiwei-zhang/vigra,cha007/vigra,mmuellner/vigra,capturePointer/vigra,cha007/vigra,dagophil/vigra,cbecker/vigra,DaveRichmond-/vigra,stuarteberg/vigra,xiwei-zhang/vigra,ThomasWalter/vigra,timoMa/vigra,dstoe/vigra,cha007/vigra,hmeine/vigra,cbecker/vigra,dstoe/vigra,cbecker/vigra,kod3r/vigra,funkey/vigra,psteinb/vigra,cbecker/vigra,martinsch/vigra,kod3r/vigra,mmuellner/vigra,ThomasWalter/vigra,funkey/vigra,kod3r/vigra,cha007/vigra,psteinb/vigra,psteinb/vigra,hmeine/vigra,mmuellner/vigra,xiwei-zhang/vigra,hmeine/vigra,funkey/vigra,kod3r/vigra,psteinb/vigra,timoMa/vigra,xiwei-zhang/vigra,timoMa/vigra,DaveRichmond-/vigra,capturePointer/vigra,capturePointer/vigra,mmuellner/vigra,dstoe/vigra,stuarteberg/vigra,ThomasWalter/vigra,dagophil/vigra,DaveRichmond-/vigra,ThomasWalter/vigra,martinsch/vigra,hmeine/vigra,timoMa/vigra,dagophil/vigra,timoMa/vigra,stuarteberg/vigra,funkey/vigra,martinsch/vigra,stuarteberg/vigra,hmeine/vigra,funkey/vigra,cha007/vigra