COMP: Fix missing ptrdiff_t error on itkNumericTraitsTest.
COMP: Fix missing ptrdiff_t error on itkNumericTraitsTest.

This fixes the compile error on gcc (Debian 4.6.1-4).

Change-Id: I43c6af5d8f999c41f9039bdeab27f2fe76c96816

hendradarwin/ITK,LucasGandel/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,rhgong/itk-with-dom,CapeDrew/DCMTK-ITK,fuentesdt/InsightToolkit-dev,LucasGandel/ITK,jcfr/ITK,jmerkow/ITK,zachary-williamson/ITK,malaterre/ITK,spinicist/ITK,Kitware/ITK,spinicist/ITK,zachary-williamson/ITK,fedral/ITK,hinerm/ITK,GEHC-Surgery/ITK,heimdali/ITK,msmolens/ITK,atsnyder/ITK,LucHermitte/ITK,eile/ITK,msmolens/ITK,richardbeare/ITK,heimdali/ITK,fbudin69500/ITK,CapeDrew/DCMTK-ITK,heimdali/ITK,rhgong/itk-with-dom,stnava/ITK,fbudin69500/ITK,vfonov/ITK,paulnovo/ITK,GEHC-Surgery/ITK,thewtex/ITK,spinicist/ITK,msmolens/ITK,stnava/ITK,fbudin69500/ITK,blowekamp/ITK,eile/ITK,jcfr/ITK,fuentesdt/InsightToolkit-dev,PlutoniumHeart/ITK,zachary-williamson/ITK,CapeDrew/DCMTK-ITK,rhgong/itk-with-dom,GEHC-Surgery/ITK,zachary-williamson/ITK,fuentesdt/InsightToolkit-dev,InsightSoftwareConsortium/ITK,GEHC-Surgery/ITK,malaterre/ITK,ajjl/ITK,heimdali/ITK,rhgong/itk-with-dom,vfonov/ITK,stnava/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK,Kitware/ITK,hendradarwin/ITK,biotrump/ITK,eile/ITK,biotrump/ITK,blowekamp/ITK,hendradarwin/ITK,fedral/ITK,BRAINSia/ITK,jcfr/ITK,ajjl/ITK,biotrump/ITK,hjmjohnson/ITK,jmerkow/ITK,fuentesdt/InsightToolkit-dev,zachary-williamson/ITK,fbudin69500/ITK,BlueBrain/ITK,thewtex/ITK,malaterre/ITK,stnava/ITK,LucasGandel/ITK,fuentesdt/InsightToolkit-dev,hinerm/ITK,atsnyder/ITK,fuentesdt/InsightToolkit-dev,fuentesdt/InsightToolkit-dev,CapeDrew/DCMTK-ITK,BRAINSia/ITK,richardbeare/ITK,eile/ITK,InsightSoftwareConsortium/ITK,spinicist/ITK,BRAINSia/ITK,richardbeare/ITK,atsnyder/ITK,eile/ITK,fbudin69500/ITK,stnava/ITK,jmerkow/ITK,rhgong/itk-with-dom,malaterre/ITK,atsnyder/ITK,msmolens/ITK,spinicist/ITK,ajjl/ITK,malaterre/ITK,LucHermitte/ITK,eile/ITK,heimdali/ITK,jcfr/ITK,GEHC-Surgery/ITK,paulnovo/ITK,hendradarwin/ITK,CapeDrew/DCMTK-ITK,eile/ITK,fuentesdt/InsightToolkit-dev,thewtex/ITK,paulnovo/ITK,biotrump/ITK,zachary-williamson/ITK,hinerm/ITK,fedral/ITK,BlueBrain/ITK,jmerkow/ITK,LucasGandel/ITK,atsnyder/ITK,blowekamp/ITK,msmolens/ITK,stnava/ITK,rhgong/itk-with-dom,spinicist/ITK,LucasGandel/ITK,thewtex/ITK,jmerkow/ITK,stnava/ITK,GEHC-Surgery/ITK,PlutoniumHeart/ITK,BlueBrain/ITK,BlueBrain/ITK,hjmjohnson/ITK,fbudin69500/ITK,PlutoniumHeart/ITK,InsightSoftwareConsortium/ITK,CapeDrew/DCMTK-ITK,LucHermitte/ITK,spinicist/ITK,vfonov/ITK,biotrump/ITK,vfonov/ITK,LucasGandel/ITK,ajjl/ITK,rhgong/itk-with-dom,hjmjohnson/ITK,hendradarwin/ITK,atsnyder/ITK,jcfr/ITK,PlutoniumHeart/ITK,fbudin69500/ITK,rhgong/itk-with-dom,LucHermitte/ITK,LucHermitte/ITK,jmerkow/ITK,CapeDrew/DCMTK-ITK,zachary-williamson/ITK,hinerm/ITK,paulnovo/ITK,jcfr/ITK,LucasGandel/ITK,LucHermitte/ITK,BlueBrain/ITK,atsnyder/ITK,thewtex/ITK,atsnyder/ITK,hinerm/ITK,LucHermitte/ITK,Kitware/ITK,CapeDrew/DCMTK-ITK,paulnovo/ITK,hjmjohnson/ITK,fedral/ITK,blowekamp/ITK,jmerkow/ITK,biotrump/ITK,malaterre/ITK,vfonov/ITK,hinerm/ITK,thewtex/ITK,ajjl/ITK,vfonov/ITK,stnava/ITK,msmolens/ITK,jcfr/ITK,heimdali/ITK,Kitware/ITK,blowekamp/ITK,stnava/ITK,thewtex/ITK,vfonov/ITK,paulnovo/ITK,richardbeare/ITK,paulnovo/ITK,fuentesdt/InsightToolkit-dev,BRAINSia/ITK,GEHC-Surgery/ITK,jcfr/ITK,LucHermitte/ITK,PlutoniumHeart/ITK,fbudin69500/ITK,vfonov/ITK,InsightSoftwareConsortium/ITK,hendradarwin/ITK,eile/ITK,InsightSoftwareConsortium/ITK,BlueBrain/ITK,hjmjohnson/ITK,hinerm/ITK,richardbeare/ITK,PlutoniumHeart/ITK,zachary-williamson/ITK,blowekamp/ITK,BlueBrain/ITK,msmolens/ITK,Kitware/ITK,PlutoniumHeart/ITK,atsnyder/ITK,BRAINSia/ITK,msmolens/ITK,LucasGandel/ITK,CapeDrew/DCMTK-ITK,malaterre/ITK,spinicist/ITK,richardbeare/ITK,blowekamp/ITK,heimdali/ITK,eile/ITK,ajjl/ITK,hendradarwin/ITK,jmerkow/ITK,hinerm/ITK,fedral/ITK,PlutoniumHeart/ITK,blowekamp/ITK,BRAINSia/ITK,biotrump/ITK,Kitware/ITK,vfonov/ITK,ajjl/ITK,BRAINSia/ITK,ajjl/ITK,zachary-williamson/ITK,fedral/ITK,GEHC-Surgery/ITK,spinicist/ITK,heimdali/ITK,hendradarwin/ITK,Kitware/ITK,BlueBrain/ITK,fedral/ITK,biotrump/ITK,paulnovo/ITK,hinerm/ITK,hjmjohnson/ITK,fedral/ITK,malaterre/ITK