fix in case system jpeg, png, gif and tiff libs are not found (avoid empty -I options to the compiler).
fix in case system jpeg, png, gif and tiff libs are not found (avoid empty
-I options to the compiler).


git-svn-id: acec3fd5b7ea1eb9e79d6329d318e8118ee2e14f@10377 27541ba8-7e3a-0410-8455-c3a389f83636

simonpf/root,lgiommi/root,nilqed/root,georgtroska/root,mattkretz/root,mhuwiler/rootauto,perovic/root,agarciamontoro/root,zzxuanyuan/root,thomaskeck/root,arch1tect0r/root,krafczyk/root,simonpf/root,sirinath/root,alexschlueter/cern-root,sbinet/cxx-root,Duraznos/root,esakellari/root,Y--/root,beniz/root,satyarth934/root,tc3t/qoot,cxx-hep/root-cern,nilqed/root,dfunke/root,gganis/root,tc3t/qoot,0x0all/ROOT,pspe/root,abhinavmoudgil95/root,mhuwiler/rootauto,simonpf/root,veprbl/root,krafczyk/root,thomaskeck/root,zzxuanyuan/root,zzxuanyuan/root,pspe/root,satyarth934/root,davidlt/root,zzxuanyuan/root,alexschlueter/cern-root,strykejern/TTreeReader,zzxuanyuan/root,evgeny-boger/root,sawenzel/root,ffurano/root5,georgtroska/root,Duraznos/root,thomaskeck/root,lgiommi/root,beniz/root,mattkretz/root,vukasinmilosevic/root,bbockelm/root,agarciamontoro/root,olifre/root,bbockelm/root,evgeny-boger/root,buuck/root,evgeny-boger/root,evgeny-boger/root,olifre/root,bbockelm/root,omazapa/root-old,abhinavmoudgil95/root,olifre/root,omazapa/root,nilqed/root,gganis/root,smarinac/root,olifre/root,perovic/root,bbockelm/root,esakellari/my_root_for_test,krafczyk/root,mkret2/root,lgiommi/root,sawenzel/root,smarinac/root,agarciamontoro/root,sawenzel/root,buuck/root,esakellari/root,davidlt/root,georgtroska/root,sawenzel/root,beniz/root,sawenzel/root,cxx-hep/root-cern,esakellari/my_root_for_test,sawenzel/root,lgiommi/root,karies/root,ffurano/root5,zzxuanyuan/root-compressor-dummy,lgiommi/root,gbitzes/root,simonpf/root,krafczyk/root,arch1tect0r/root,buuck/root,krafczyk/root,mkret2/root,buuck/root,veprbl/root,olifre/root,smarinac/root,esakellari/root,nilqed/root,alexschlueter/cern-root,nilqed/root,beniz/root,BerserkerTroll/root,veprbl/root,gbitzes/root,esakellari/root,dfunke/root,karies/root,gbitzes/root,mkret2/root,satyarth934/root,0x0all/ROOT,sirinath/root,sirinath/root,mhuwiler/rootauto,buuck/root,root-mirror/root,perovic/root,CristinaCristescu/root,olifre/root,olifre/root,simonpf/root,veprbl/root,arch1tect0r/root,root-mirror/root,satyarth934/root,karies/root,gganis/root,abhinavmoudgil95/root,nilqed/root,krafczyk/root,karies/root,buuck/root,sawenzel/root,Y--/root,omazapa/root-old,kirbyherm/root-r-tools,evgeny-boger/root,smarinac/root,esakellari/my_root_for_test,omazapa/root,bbockelm/root,BerserkerTroll/root,sirinath/root,mkret2/root,Y--/root,esakellari/my_root_for_test,zzxuanyuan/root-compressor-dummy,agarciamontoro/root,veprbl/root,georgtroska/root,Duraznos/root,abhinavmoudgil95/root,olifre/root,karies/root,arch1tect0r/root,Y--/root,vukasinmilosevic/root,zzxuanyuan/root-compressor-dummy,sirinath/root,kirbyherm/root-r-tools,strykejern/TTreeReader,kirbyherm/root-r-tools,veprbl/root,mattkretz/root,bbockelm/root,omazapa/root,gganis/root,0x0all/ROOT,pspe/root,zzxuanyuan/root,lgiommi/root,karies/root,CristinaCristescu/root,nilqed/root,vukasinmilosevic/root,simonpf/root,davidlt/root,vukasinmilosevic/root,esakellari/my_root_for_test,cxx-hep/root-cern,root-mirror/root,arch1tect0r/root,thomaskeck/root,gbitzes/root,gganis/root,zzxuanyuan/root-compressor-dummy,gganis/root,buuck/root,dfunke/root,pspe/root,mkret2/root,lgiommi/root,Duraznos/root,ffurano/root5,mattkretz/root,mattkretz/root,gbitzes/root,vukasinmilosevic/root,Y--/root,agarciamontoro/root,esakellari/root,esakellari/my_root_for_test,0x0all/ROOT,karies/root,satyarth934/root,satyarth934/root,sbinet/cxx-root,bbockelm/root,pspe/root,sbinet/cxx-root,pspe/root,abhinavmoudgil95/root,sawenzel/root,dfunke/root,veprbl/root,kirbyherm/root-r-tools,nilqed/root,bbockelm/root,0x0all/ROOT,beniz/root,BerserkerTroll/root,satyarth934/root,mattkretz/root,gganis/root,perovic/root,CristinaCristescu/root,omazapa/root,davidlt/root,strykejern/TTreeReader,ffurano/root5,olifre/root,kirbyherm/root-r-tools,olifre/root,abhinavmoudgil95/root,mattkretz/root,thomaskeck/root,Dr15Jones/root,perovic/root,sawenzel/root,sbinet/cxx-root,davidlt/root,Duraznos/root,sbinet/cxx-root,mhuwiler/rootauto,sbinet/cxx-root,gbitzes/root,bbockelm/root,satyarth934/root,dfunke/root,evgeny-boger/root,esakellari/root,thomaskeck/root,evgeny-boger/root,krafczyk/root,jrtomps/root,jrtomps/root,omazapa/root,Duraznos/root,satyarth934/root,CristinaCristescu/root,mattkretz/root,arch1tect0r/root,jrtomps/root,krafczyk/root,omazapa/root,arch1tect0r/root,omazapa/root,mkret2/root,Duraznos/root,tc3t/qoot,tc3t/qoot,omazapa/root-old,gganis/root,pspe/root,omazapa/root,smarinac/root,sawenzel/root,sirinath/root,dfunke/root,beniz/root,olifre/root,alexschlueter/cern-root,strykejern/TTreeReader,georgtroska/root,smarinac/root,omazapa/root-old,jrtomps/root,evgeny-boger/root,BerserkerTroll/root,mhuwiler/rootauto,tc3t/qoot,cxx-hep/root-cern,sirinath/root,root-mirror/root,0x0all/ROOT,arch1tect0r/root,evgeny-boger/root,mhuwiler/rootauto,jrtomps/root,alexschlueter/cern-root,dfunke/root,simonpf/root,omazapa/root,georgtroska/root,georgtroska/root,Y--/root,ffurano/root5,sbinet/cxx-root,Duraznos/root,simonpf/root,gganis/root,alexschlueter/cern-root,tc3t/qoot,perovic/root,0x0all/ROOT,perovic/root,zzxuanyuan/root,veprbl/root,sirinath/root,esakellari/my_root_for_test,CristinaCristescu/root,vukasinmilosevic/root,buuck/root,kirbyherm/root-r-tools,root-mirror/root,CristinaCristescu/root,BerserkerTroll/root,gbitzes/root,beniz/root,mattkretz/root,mattkretz/root,BerserkerTroll/root,agarciamontoro/root,beniz/root,mhuwiler/rootauto,zzxuanyuan/root,BerserkerTroll/root,nilqed/root,sbinet/cxx-root,zzxuanyuan/root-compressor-dummy,BerserkerTroll/root,Dr15Jones/root,jrtomps/root,simonpf/root,omazapa/root-old,agarciamontoro/root,jrtomps/root,davidlt/root,krafczyk/root,0x0all/ROOT,esakellari/root,perovic/root,esakellari/root,mhuwiler/rootauto,abhinavmoudgil95/root,esakellari/my_root_for_test,perovic/root,davidlt/root,mhuwiler/rootauto,omazapa/root-old,sirinath/root,strykejern/TTreeReader,arch1tect0r/root,Y--/root,zzxuanyuan/root,georgtroska/root,cxx-hep/root-cern,zzxuanyuan/root,simonpf/root,mkret2/root,mkret2/root,CristinaCristescu/root,esakellari/my_root_for_test,tc3t/qoot,davidlt/root,cxx-hep/root-cern,krafczyk/root,lgiommi/root,evgeny-boger/root,gbitzes/root,lgiommi/root,veprbl/root,zzxuanyuan/root,dfunke/root,0x0all/ROOT,CristinaCristescu/root,sbinet/cxx-root,omazapa/root-old,abhinavmoudgil95/root,davidlt/root,esakellari/root,BerserkerTroll/root,dfunke/root,smarinac/root,arch1tect0r/root,thomaskeck/root,evgeny-boger/root,Duraznos/root,root-mirror/root,BerserkerTroll/root,sirinath/root,sbinet/cxx-root,esakellari/root,root-mirror/root,tc3t/qoot,mattkretz/root,buuck/root,georgtroska/root,perovic/root,mhuwiler/rootauto,davidlt/root,sawenzel/root,Dr15Jones/root,beniz/root,omazapa/root-old,vukasinmilosevic/root,lgiommi/root,root-mirror/root,zzxuanyuan/root-compressor-dummy,root-mirror/root,esakellari/my_root_for_test,Duraznos/root,georgtroska/root,arch1tect0r/root,alexschlueter/cern-root,smarinac/root,agarciamontoro/root,thomaskeck/root,satyarth934/root,ffurano/root5,agarciamontoro/root,Dr15Jones/root,cxx-hep/root-cern,gbitzes/root,buuck/root,vukasinmilosevic/root,smarinac/root,vukasinmilosevic/root,karies/root,bbockelm/root,beniz/root,gganis/root,jrtomps/root,bbockelm/root,BerserkerTroll/root,CristinaCristescu/root,perovic/root,kirbyherm/root-r-tools,strykejern/TTreeReader,pspe/root,zzxuanyuan/root-compressor-dummy,Duraznos/root,pspe/root,zzxuanyuan/root-compressor-dummy,Dr15Jones/root,abhinavmoudgil95/root,veprbl/root,dfunke/root,omazapa/root,abhinavmoudgil95/root,pspe/root,agarciamontoro/root,omazapa/root-old,dfunke/root,tc3t/qoot,karies/root,karies/root,krafczyk/root,CristinaCristescu/root,root-mirror/root,vukasinmilosevic/root,zzxuanyuan/root-compressor-dummy,gbitzes/root,Y--/root,nilqed/root,lgiommi/root,CristinaCristescu/root,abhinavmoudgil95/root,davidlt/root,Y--/root,Dr15Jones/root,thomaskeck/root,Y--/root,strykejern/TTreeReader,sbinet/cxx-root,thomaskeck/root,veprbl/root,nilqed/root,sirinath/root,mkret2/root,cxx-hep/root-cern,mkret2/root,vukasinmilosevic/root,tc3t/qoot,mhuwiler/rootauto,zzxuanyuan/root-compressor-dummy,mkret2/root,smarinac/root,jrtomps/root,gbitzes/root,zzxuanyuan/root-compressor-dummy,agarciamontoro/root,Y--/root,satyarth934/root,zzxuanyuan/root,ffurano/root5,omazapa/root-old,omazapa/root-old,root-mirror/root,jrtomps/root,gganis/root,beniz/root,jrtomps/root,pspe/root,Dr15Jones/root,omazapa/root,karies/root,buuck/root,esakellari/root,simonpf/root,georgtroska/root