COMP: Updating DCMTK compilation for Ninja
COMP: Updating DCMTK compilation for Ninja

By-products of building DCMTK as an external project
are required for Ninja to build the targets that
require these files. The function ExternalProject_Add()
only supports BUILD_BYPRODUCTS option for CMake >= 3.2.
If one tries to build DCMTK with Ninja and CMake < 3.2,
an error is returned during configuration.

Change-Id: I0522ec6d476d62f0014c81344cb3f70af177d86a

PlutoniumHeart/ITK,fbudin69500/ITK,hjmjohnson/ITK,spinicist/ITK,spinicist/ITK,blowekamp/ITK,richardbeare/ITK,PlutoniumHeart/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,PlutoniumHeart/ITK,hjmjohnson/ITK,vfonov/ITK,Kitware/ITK,richardbeare/ITK,stnava/ITK,Kitware/ITK,richardbeare/ITK,PlutoniumHeart/ITK,stnava/ITK,LucasGandel/ITK,stnava/ITK,PlutoniumHeart/ITK,blowekamp/ITK,LucasGandel/ITK,thewtex/ITK,vfonov/ITK,LucasGandel/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,stnava/ITK,Kitware/ITK,vfonov/ITK,thewtex/ITK,LucasGandel/ITK,LucasGandel/ITK,stnava/ITK,vfonov/ITK,hjmjohnson/ITK,blowekamp/ITK,stnava/ITK,Kitware/ITK,vfonov/ITK,malaterre/ITK,thewtex/ITK,fbudin69500/ITK,richardbeare/ITK,stnava/ITK,richardbeare/ITK,richardbeare/ITK,thewtex/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,spinicist/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,fbudin69500/ITK,malaterre/ITK,fbudin69500/ITK,fbudin69500/ITK,BRAINSia/ITK,blowekamp/ITK,spinicist/ITK,vfonov/ITK,PlutoniumHeart/ITK,stnava/ITK,malaterre/ITK,vfonov/ITK,Kitware/ITK,spinicist/ITK,spinicist/ITK,hjmjohnson/ITK,LucasGandel/ITK,PlutoniumHeart/ITK,richardbeare/ITK,fbudin69500/ITK,malaterre/ITK,malaterre/ITK,blowekamp/ITK,thewtex/ITK,blowekamp/ITK,vfonov/ITK,BRAINSia/ITK,BRAINSia/ITK,spinicist/ITK,LucasGandel/ITK,blowekamp/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,BRAINSia/ITK,LucasGandel/ITK,BRAINSia/ITK,PlutoniumHeart/ITK,thewtex/ITK,fbudin69500/ITK,malaterre/ITK,thewtex/ITK,blowekamp/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,spinicist/ITK,hjmjohnson/ITK,fbudin69500/ITK,spinicist/ITK,malaterre/ITK,stnava/ITK,vfonov/ITK,Kitware/ITK