Fix building of tests in Xcode.

That dreaded CMake bug AGAIN.

src/MagnumPlugins/AnyAudioImporter/CMakeLists.txt

@@ -56,7 +56,9 @@ target_link_libraries(AnyAudioImporter Magnum::Magnum Magnum::Audio)
 install(FILES ${AnyAudioImporter_HEADERS} DESTINATION ${MAGNUM_PLUGINS_INCLUDE_INSTALL_DIR}/AnyAudioImporter)
 
 if(BUILD_TESTS)
-    add_library(MagnumAnyAudioImporterTestLib STATIC $<TARGET_OBJECTS:AnyAudioImporterObjects>)
+    add_library(MagnumAnyAudioImporterTestLib STATIC
+        $<TARGET_OBJECTS:AnyAudioImporterObjects>
+        ${PROJECT_SOURCE_DIR}/src/dummy.cpp) # XCode workaround, see file comment for details
     target_include_directories(MagnumAnyAudioImporterTestLib PUBLIC ${PROJECT_SOURCE_DIR}/src)
     target_link_libraries(MagnumAnyAudioImporterTestLib Magnum::Magnum Magnum::Audio)
     add_subdirectory(Test)

src/MagnumPlugins/AnyImageConverter/CMakeLists.txt

@@ -54,7 +54,9 @@ target_link_libraries(AnyImageConverter Magnum::Magnum)
 install(FILES ${AnyImageConverter_HEADERS} DESTINATION ${MAGNUM_PLUGINS_INCLUDE_INSTALL_DIR}/AnyImageConverter)
 
 if(BUILD_TESTS)
-    add_library(MagnumAnyImageConverterTestLib STATIC $<TARGET_OBJECTS:AnyImageConverterObjects>)
+    add_library(MagnumAnyImageConverterTestLib STATIC
+        $<TARGET_OBJECTS:AnyImageConverterObjects>
+        ${PROJECT_SOURCE_DIR}/src/dummy.cpp) # XCode workaround, see file comment for details
     target_include_directories(MagnumAnyImageConverterTestLib PUBLIC ${PROJECT_SOURCE_DIR}/src)
     target_link_libraries(MagnumAnyImageConverterTestLib Magnum::Magnum)
     add_subdirectory(Test)

src/MagnumPlugins/AnyImageImporter/CMakeLists.txt

@@ -66,7 +66,9 @@ install(FILES ${AnyImageImporter_HEADERS} DESTINATION ${MAGNUM_PLUGINS_INCLUDE_I
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/configure.h DESTINATION ${MAGNUM_PLUGINS_INCLUDE_INSTALL_DIR}/AnyImageImporter)
 
 if(BUILD_TESTS)
-    add_library(MagnumAnyImageImporterTestLib STATIC $<TARGET_OBJECTS:AnyImageImporterObjects>)
+    add_library(MagnumAnyImageImporterTestLib STATIC
+        $<TARGET_OBJECTS:AnyImageImporterObjects>
+        ${PROJECT_SOURCE_DIR}/src/dummy.cpp) # XCode workaround, see file comment for details
     target_include_directories(MagnumAnyImageImporterTestLib PUBLIC
         ${PROJECT_SOURCE_DIR}/src
         ${PROJECT_BINARY_DIR}/src)

src/MagnumPlugins/AnySceneImporter/CMakeLists.txt

@@ -55,7 +55,9 @@ target_link_libraries(AnySceneImporter Magnum::Magnum)
 install(FILES ${AnySceneImporter_HEADERS} DESTINATION ${MAGNUM_PLUGINS_INCLUDE_INSTALL_DIR}/AnySceneImporter)
 
 if(BUILD_TESTS)
-    add_library(MagnumAnySceneImporterTestLib STATIC $<TARGET_OBJECTS:AnySceneImporterObjects>)
+    add_library(MagnumAnySceneImporterTestLib STATIC
+        $<TARGET_OBJECTS:AnySceneImporterObjects>
+        ${PROJECT_SOURCE_DIR}/src/dummy.cpp) # XCode workaround, see file comment for details
     target_include_directories(MagnumAnySceneImporterTestLib PUBLIC ${PROJECT_SOURCE_DIR}/src)
     target_link_libraries(MagnumAnySceneImporterTestLib Magnum::Magnum)
     add_subdirectory(Test)