CMake: Add helper to ensure vcpkg DLLs are copied to the output dir

The BUILD_RPATH/INSTALL_RPATH CMake infrastructure is not supported
on Windows, but we want to ensure Ladybird executables are runnable
after the build phase so there can be an efficient dev loop.
lagom_copy_runtime_dlls() can be used by executable targets so all
their dependent dlls are copied to their output directory in their
post build step.

Meta/CMake/targets.cmake

@@ -18,6 +18,18 @@ function(lagom_generate_export_header name fs_name)
     generate_export_header(${name} EXPORT_MACRO_NAME ${fs_name_upper}_API EXPORT_FILE_NAME "Export.h")
 endfunction()
 
+function(lagom_copy_runtime_dlls target_name)
+    if (WIN32 AND BUILD_SHARED_LIBS)
+        add_custom_command(TARGET ${target_name} POST_BUILD
+            COMMAND ${CMAKE_COMMAND}
+                -E copy_if_different
+                $<TARGET_RUNTIME_DLLS:${target_name}>
+                $<TARGET_FILE_DIR:${target_name}>
+            COMMAND_EXPAND_LISTS
+        )
+    endif()
+endfunction()
+
 function(lagom_lib target_name fs_name)
     cmake_parse_arguments(LAGOM_LIBRARY "EXPLICIT_SYMBOL_EXPORT" "LIBRARY_TYPE" "SOURCES;LIBS" ${ARGN})
     string(REPLACE "Lib" "" library ${target_name})
@@ -80,6 +92,7 @@ function(lagom_test source)
     endif()
     add_executable(${LAGOM_TEST_NAME} ${source})
     target_link_libraries(${LAGOM_TEST_NAME} PRIVATE AK LibCore LibFileSystem LibTest ${LAGOM_TEST_CUSTOM_MAIN} ${LAGOM_TEST_LIBS})
+    lagom_copy_runtime_dlls(${LAGOM_TEST_NAME})
 
     if (WIN32)
         target_include_directories(${LAGOM_TEST_NAME} PRIVATE ${PTHREAD_INCLUDE_DIR})
@@ -117,6 +130,7 @@ function(ladybird_bin name)
     add_executable(${name} ${SOURCES} ${GENERATED_SOURCES})
     add_executable(Lagom::${name} ALIAS ${name})
     target_link_libraries(${name} PUBLIC GenericClangPlugin)
+    lagom_copy_runtime_dlls(${name})
     install(
             TARGETS ${target_name}
             EXPORT LagomTargets

Tests/LibWeb/test-web/CMakeLists.txt

@@ -9,6 +9,7 @@ set(SOURCES
 add_executable(test-web ${SOURCES})
 add_dependencies(test-web ladybird_build_resource_files ImageDecoder RequestServer WebContent WebWorker)
 target_link_libraries(test-web PRIVATE AK LibCore LibDiff LibFileSystem LibGfx LibImageDecoderClient LibIPC LibJS LibMain LibRequests LibURL LibWeb LibWebView)
+lagom_copy_runtime_dlls(test-web)
 
 if (APPLE)
     target_compile_definitions(test-web PRIVATE LADYBIRD_BINARY_PATH="$<TARGET_FILE_DIR:ladybird>")
@@ -16,13 +17,6 @@ elseif (WIN32)
     target_link_libraries(test-web PRIVATE LibDevTools)
     find_package(pthread REQUIRED)
     target_include_directories(test-web PRIVATE $<BUILD_INTERFACE:${PTHREAD_INCLUDE_DIR}>)
-    add_custom_command(TARGET test-web POST_BUILD
-        COMMAND ${CMAKE_COMMAND}
-            -E copy_if_different
-            $<TARGET_RUNTIME_DLLS:test-web>
-            $<TARGET_FILE_DIR:test-web>
-        COMMAND_EXPAND_LISTS
-    )
 endif()
 
 # FIXME: Increase support for building targets on Windows

UI/Qt/CMakeLists.txt

@@ -15,6 +15,7 @@ target_sources(ladybird PRIVATE
     ladybird.qrc
 )
 target_link_libraries(ladybird PRIVATE Qt::Core Qt::Gui Qt::Widgets)
+lagom_copy_runtime_dlls(ladybird)
 create_ladybird_bundle(ladybird)
 
 if (WIN32)
@@ -29,10 +30,6 @@ qt_deploy_runtime_dependencies(
 ")
 
     add_custom_command(TARGET ladybird POST_BUILD
-        COMMAND ${CMAKE_COMMAND}
-            -E copy_if_different
-            $<TARGET_RUNTIME_DLLS:ladybird>
-            $<TARGET_FILE_DIR:ladybird>
         COMMAND ${CMAKE_COMMAND}
             -P ${ladybird_deploy_script}
         COMMAND_EXPAND_LISTS