Meta: Handle output directories for multi-config CMake generators

For Ninja Multi-Config, Xcode and Visual Studio, the way we set up our
output directories would result in exectuables that can't run from the
build directory. Add the same sauce that we added to Jakt to insert
``$<CONFIG>`` where appropriate.

Author: ADKaster

Ladybird/CMakeLists.txt

@@ -188,7 +188,7 @@ function(set_helper_process_properties)
         # Store helper processes in the same bundle directory as the main application
         set_target_properties(${targets} PROPERTIES RUNTIME_OUTPUT_DIRECTORY "$<TARGET_FILE_DIR:ladybird>")
     else()
-        set_target_properties(${targets} PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_LIBEXECDIR}")
+        set_target_properties(${targets} PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${IN_BUILD_PREFIX}${CMAKE_INSTALL_LIBEXECDIR}")
 
         if (NOT CMAKE_INSTALL_LIBEXECDIR STREQUAL "libexec")
             set_source_files_properties(Utilities.cpp PROPERTIES COMPILE_DEFINITIONS LADYBIRD_LIBEXECDIR="${CMAKE_INSTALL_LIBEXECDIR}")
@@ -257,7 +257,7 @@ create_ladybird_bundle(ladybird)
 set_helper_process_properties(${ladybird_helper_processes})
 
 include(cmake/ResourceFiles.cmake)
-set(resource_base_dir "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_DATADIR}/Lagom")
+set(resource_base_dir "${CMAKE_BINARY_DIR}/${IN_BUILD_PREFIX}${CMAKE_INSTALL_DATADIR}/Lagom")
 if (APPLE)
     set(resource_base_dir "$<TARGET_BUNDLE_DIR:ladybird>/Contents/Resources")
 endif()

Meta/CMake/lagom_install_options.cmake

@@ -8,11 +8,18 @@ endif()
 
 include(GNUInstallDirs) # make sure to include before we mess w/RPATH
 
+# Handle multi-config generators (e.g. MSVC, Xcode, Ninja Multi-Config)
+get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+set(IN_BUILD_PREFIX "")
+if (is_multi_config)
+    set(IN_BUILD_PREFIX "$<CONFIG>/")
+endif()
+
 # Mirror the structure of the installed tree to ensure that rpaths
 # always remain valid.
-set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_BINDIR}")
-set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR}")
-set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR}")
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${IN_BUILD_PREFIX}${CMAKE_INSTALL_BINDIR}")
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${IN_BUILD_PREFIX}${CMAKE_INSTALL_LIBDIR}")
+set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${IN_BUILD_PREFIX}${CMAKE_INSTALL_LIBDIR}")
 
 set(CMAKE_SKIP_BUILD_RPATH FALSE)
 set(CMAKE_BUILD_WITH_INSTALL_RPATH TRUE)