build: The flags are already passed explicitly do not also add to cflags

CMakeLists.txt

 cmake_minimum_required(VERSION 2.8.8)
 
-if (APPLE)
-  if(NOT CMAKE_OSX_DEPLOYMENT_TARGET)
-    message(WARNING "Ensure that CMAKE_OSX_SYSROOT, CMAKE_OSX_DEPLOYMENT_TARGET are set correctly")
-    set(CMAKE_OSX_ARCHITECTURES "x86_64" CACHE STRING "By default, build for 64-bit Leopard")
-  endif()
-endif()
-
 project(VeloViewSuperBuild)
 set (SuperBuild_CMAKE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/CMake")
 set (SuperBuild_PROJECTS_DIR "${CMAKE_CURRENT_SOURCE_DIR}/Projects")
@@ -76,11 +69,6 @@ else ()
   set (ld_library_path "${install_location}/lib:$ENV{LD_LIBRARY_PATH}")
 endif()
 
-if (APPLE)
-  set (cflags "${cflags} -arch x86_64 -mmacosx-version-min=${CMAKE_OSX_DEPLOYMENT_TARGET} -sysroot=${CMAKE_OSX_SYSROOT} ")
-  set (cppflags "${cppflags} -arch x86_64 -mmacosx-version-min=${CMAKE_OSX_DEPLOYMENT_TARGET} -sysroot=${CMAKE_OSX_SYSROOT} ")
-  set (cxxflags "${cxxflags} -arch x86_64 -mmacosx-version-min=${CMAKE_OSX_DEPLOYMENT_TARGET} -sysroot=${CMAKE_OSX_SYSROOT} ")
-endif()
 set (prefix_path "${install_location}")
 
 # merge in default/user-specified CMake flags.