COMP: Remove ep_build_command additions

Fails in expansion of <BUILD_DIR>.

Author: thewtex

CMakeLists.txt

@@ -29,12 +29,6 @@ if(ITKPythonPackage_USE_TBB)
     )
 endif()
 
-if(${CMAKE_GENERATOR} STREQUAL "Ninja")
-  include(ProcessorCount)
-  ProcessorCount(n_processors)
-  set(ep_build_command BUILD_COMMAND ${CMAKE_COMMAND} --build <BUILD_DIR> -- -j${n_processors} -l${n_processors})
-endif()
-
 if(ITKPythonPackage_SUPERBUILD)
 
   #-----------------------------------------------------------------------------
@@ -123,7 +117,6 @@ if(ITKPythonPackage_SUPERBUILD)
     ExternalProject_add(oneTBB
       URL https://github.com/oneapi-src/oneTBB/archive/refs/tags/v2021.9.0.tar.gz
       URL_HASH SHA256=1ce48f34dada7837f510735ff1172f6e2c261b09460e3bf773b49791d247d24e
-      ${ep_build_command}
       CMAKE_ARGS
         -DTBB_TEST:BOOL=OFF
         -DCMAKE_BUILD_TYPE:STRING=Release
@@ -272,7 +265,6 @@ if(ITKPythonPackage_SUPERBUILD)
 
     ExternalProject_add(ITK
       DOWNLOAD_COMMAND ""
-      ${ep_build_command}
       SOURCE_DIR ${ITK_SOURCE_DIR}
       BINARY_DIR ${ITK_BINARY_DIR}
       PREFIX "ITKp"