message: use a source zip for ospcommon (prevents extra rebuilds)
diff: @@ -29,9 +29,7 @@ ExternalProject_Add(${COMPONENT_NAME}
  STAMP_DIR ${COMPONENT_NAME}/stamp
  SOURCE_DIR ${COMPONENT_NAME}/src
  BINARY_DIR ${COMPONENT_NAME}/build
  - GIT_REPOSITORY https://github.com/ospray/ospcommon
  - GIT_TAG master
  - GIT_SHALLOW ON
  + URL "https://github.com/ospray/ospcommon/archive/master.zip"
  CMAKE_ARGS
  -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
  -DCMAKE_INSTALL_PREFIX:PATH=${COMPONENT_PATH}
  