STYLE: Remove unused ELASTIX_USE_OPENMP option and OpenMP compiler flags

The use of OpenMP was merely experimental and was switched off already in C++ code.

CMakeLists.txt

@@ -128,23 +128,6 @@ if(ELASTIX_USE_EIGEN)
   add_definitions(-DELASTIX_USE_EIGEN)
 endif()
 
-#---------------------------------------------------------------------
-# Find OpenMP
-mark_as_advanced(ELASTIX_USE_OPENMP)
-option(ELASTIX_USE_OPENMP "Use OpenMP to speed up certain computations." ON)
-
-if(ELASTIX_USE_OPENMP)
-  find_package(OpenMP QUIET)
-  if(OPENMP_FOUND)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
-    #  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}
-    #  ${OpenMP_EXE_LINKER_FLAGS}")
-    include_directories(${OpenMP_CXX_INCLUDE_DIRS})
-    link_libraries(${OpenMP_CXX_LIBRARIES})
-    add_definitions(-DELASTIX_USE_OPENMP)
-  endif()
-endif()
-
 #---------------------------------------------------------------------
 # Set single (build-tree) output directories for all executables and libraries.
 # This makes it easier to create an elxUseFile.cmake, that users can

dox/externalproject/CMakeLists.txt

@@ -6,12 +6,6 @@ cmake_minimum_required(VERSION 3.16.3)
 
 find_package(Elastix REQUIRED)
 
-# Elastix might use OpenMP.
-find_package(OpenMP QUIET)
-if(OPENMP_FOUND)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
-endif()
-
 # Use the version of ITK from Elastix.
 if ( DEFINED ELASTIX_ITK_DIR)
   set(ITK_DIR "${ELASTIX_ITK_DIR}" CACHE PATH "ITK_DIR from Elastix" FORCE)