resolved pybind issue 550

resources/pybind11/CMakeLists.txt

@@ -93,7 +93,7 @@ function(pybind11_add_module target_name)
     # visibility to hidden (very important to obtain small binaries)
      string(TOUPPER "${CMAKE_BUILD_TYPE}" U_CMAKE_BUILD_TYPE)
      if (NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
-      # Check for Link Time Optimization support (GCC/Clang)
+#      # Check for Link Time Optimization support (GCC/Clang)
        check_cxx_compiler_flag("-flto" HAS_LTO_FLAG)
        if(HAS_LTO_FLAG AND NOT CYGWIN)
           target_compile_options(${target_name} PRIVATE -flto)
@@ -106,11 +106,13 @@ function(pybind11_add_module target_name)
            target_compile_options(${target_name} PRIVATE -ipo)
          endif()
        endif()
-
-      # Default symbol visibility
+#
+      if(NOT APPLE)
+#      # Default symbol visibility
         target_compile_options(${target_name} PRIVATE "-fvisibility=hidden")
+      endif()
 
-      # Strip unnecessary sections of the binary on Linux/Mac OS
+#      # Strip unnecessary sections of the binary on Linux/Mac OS
       if(CMAKE_STRIP)
          if(APPLE)
            add_custom_command(TARGET ${target_name} POST_BUILD