[cmake] copy parts of pybind11/CMakeLists.txt into DunePybindxiUtils.cmake

cmake/modules/DunePybindxiUtils.cmake

+# The code below is a renamed copy of parts of ../../pybind11/CMakeLists.txt,
+# see ../../pybind11/LICENSE for license information.
+
+
+# Build a Python extension module:
+# dune_pybindxi_add_module(<name> source1 [source2 ...])
+#
+function(dune_pybindxi_add_module target_name)
+  add_library(${target_name} MODULE ${ARGN})
+  target_include_directories(${target_name}
+    PRIVATE ${PYBIND11_INCLUDE_DIR}
+    PRIVATE ${PYTHON_INCLUDE_DIRS})
+
+  # The prefix and extension are provided by FindPythonLibsNew.cmake
+  set_target_properties(${target_name} PROPERTIES PREFIX "${PYTHON_MODULE_PREFIX}")
+  set_target_properties(${target_name} PROPERTIES SUFFIX "${PYTHON_MODULE_EXTENSION}")
+
+  if(WIN32 OR CYGWIN)
+    # Link against the Python shared library on Windows
+    target_link_libraries(${target_name} PRIVATE ${PYTHON_LIBRARIES})
+  elseif(APPLE)
+    # It's quite common to have multiple copies of the same Python version
+    # installed on one's system. E.g.: one copy from the OS and another copy
+    # that's statically linked into an application like Blender or Maya.
+    # If we link our plugin library against the OS Python here and import it
+    # into Blender or Maya later on, this will cause segfaults when multiple
+    # conflicting Python instances are active at the same time (even when they
+    # are of the same version).
+
+    # Windows is not affected by this issue since it handles DLL imports
+    # differently. The solution for Linux and Mac OS is simple: we just don't
+    # link against the Python library. The resulting shared library will have
+    # missing symbols, but that's perfectly fine -- they will be resolved at
+    # import time.
+
+    target_link_libraries(${target_name} PRIVATE "-undefined dynamic_lookup")
+  endif()
+
+  if(NOT MSVC)
+    # Make sure C++11/14 are enabled
+    target_compile_options(${target_name} PUBLIC ${PYBIND11_CPP_STANDARD})
+
+    # Enable link time optimization and set the default symbol
+    # visibility to hidden (very important to obtain small binaries)
+    string(TOUPPER "${CMAKE_BUILD_TYPE}" U_CMAKE_BUILD_TYPE)
+    if (NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
+      # Check for Link Time Optimization support (GCC/Clang)
+      check_cxx_compiler_flag("-flto" HAS_LTO_FLAG)
+      if(HAS_LTO_FLAG AND NOT CYGWIN)
+        target_compile_options(${target_name} PRIVATE -flto)
+      endif()
+
+      # Intel equivalent to LTO is called IPO
+      if(CMAKE_CXX_COMPILER_ID MATCHES "Intel")
+        check_cxx_compiler_flag("-ipo" HAS_IPO_FLAG)
+        if(HAS_IPO_FLAG)
+          target_compile_options(${target_name} PRIVATE -ipo)
+        endif()
+      endif()
+
+      # Default symbol visibility
+      target_compile_options(${target_name} PRIVATE "-fvisibility=hidden")
+
+      # Strip unnecessary sections of the binary on Linux/Mac OS
+      if(CMAKE_STRIP)
+        if(APPLE)
+          add_custom_command(TARGET ${target_name} POST_BUILD
+                             COMMAND ${CMAKE_STRIP} -u -r $<TARGET_FILE:${target_name}>)
+        else()
+          add_custom_command(TARGET ${target_name} POST_BUILD
+                             COMMAND ${CMAKE_STRIP} $<TARGET_FILE:${target_name}>)
+        endif()
+      endif()
+    endif()
+  elseif(MSVC)
+    # /MP enables multithreaded builds (relevant when there are many files), /bigobj is
+    # needed for bigger binding projects due to the limit to 64k addressable sections
+    target_compile_options(${target_name} PRIVATE /MP /bigobj)
+
+    # Enforce link time code generation on MSVC, except in debug mode
+    target_compile_options(${target_name} PRIVATE $<$<NOT:$<CONFIG:Debug>>:/GL>)
+
+    # Fancy generator expressions don't work with linker flags, for reasons unknown
+    set_property(TARGET ${target_name} APPEND_STRING PROPERTY LINK_FLAGS_RELEASE /LTCG)
+    set_property(TARGET ${target_name} APPEND_STRING PROPERTY LINK_FLAGS_MINSIZEREL /LTCG)
+    set_property(TARGET ${target_name} APPEND_STRING PROPERTY LINK_FLAGS_RELWITHDEBINFO /LTCG)
+  endif()
+endfunction()
+
+
+#set(PYBIND11_HEADERS
+#  include/pybind11/attr.h
+#  include/pybind11/cast.h
+#  include/pybind11/chrono.h
+#  include/pybind11/common.h
+#  include/pybind11/complex.h
+#  include/pybind11/descr.h
+#  include/pybind11/eigen.h
+#  include/pybind11/eval.h
+#  include/pybind11/functional.h
+#  include/pybind11/numpy.h
+#  include/pybind11/operators.h
+#  include/pybind11/pybind11.h
+#  include/pybind11/pytypes.h
+#  include/pybind11/stl.h
+#  include/pybind11/stl_bind.h
+#  include/pybind11/typeid.h
+#)
+#string(REPLACE "include/" "${CMAKE_CURRENT_SOURCE_DIR}/include/"
+#       PYBIND11_HEADERS "${PYBIND11_HEADERS}")
+