build(cmake): add install target

This makes dynarmic installable, and also adds a CMake package config
file, that allows projects to use `find_package(dynarmic)` to import the
library.

I know #636 adds the same thing, but while experimenting with the
different install options in
https://github.com/merryhime/dynarmic/pull/636#discussion_r725656034
I ended up with a working patch, so I'm proposing this as well. This
implements solution 2.

CMakeLists.txt

@@ -171,3 +171,32 @@ add_subdirectory(src/dynarmic)
 if (DYNARMIC_TESTS)
     add_subdirectory(tests)
 endif()
+
+#
+# Install
+#
+if (MASTER_PROJECT)
+    include(GNUInstallDirs)
+    include(CMakePackageConfigHelpers)
+
+    install(TARGETS dynarmic EXPORT dynarmicTargets)
+    install(EXPORT dynarmicTargets
+        NAMESPACE dynarmic::
+        DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/dynarmic"
+    )
+
+    configure_package_config_file(CMakeModules/dynarmicConfig.cmake.in
+        dynarmicConfig.cmake
+        INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/dynarmic"
+    )
+    write_basic_package_version_file(dynarmicConfigVersion.cmake
+        COMPATIBILITY SameMajorVersion
+    )
+    install(FILES
+        "${CMAKE_CURRENT_BINARY_DIR}/dynarmicConfig.cmake"
+        "${CMAKE_CURRENT_BINARY_DIR}/dynarmicConfigVersion.cmake"
+        DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/dynarmic"
+    )
+
+    install(DIRECTORY src/dynarmic TYPE INCLUDE FILES_MATCHING PATTERN "*.h")
+endif()

CMakeModules/dynarmicConfig.cmake.in

@@ -0,0 +1,5 @@
+@PACKAGE_INIT@
+
+include("${CMAKE_CURRENT_LIST_DIR}/@PROJECT_NAME@Targets.cmake")
+
+check_required_components(@PROJECT_NAME@)

externals/CMakeLists.txt

@@ -24,9 +24,7 @@ target_include_directories(mp INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE
 # robin-map
 
 if (NOT TARGET tsl::robin_map)
-    add_library(robin_map INTERFACE)
+    add_subdirectory(robin-map)
-    add_library(tsl::robin_map ALIAS robin_map)
-    target_include_directories(robin_map SYSTEM INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/robin-map/include>")
 endif()
 
 # vixl

src/dynarmic/CMakeLists.txt

@@ -350,7 +350,7 @@ if (ARCHITECTURE STREQUAL "x86_64")
         endif()
     elseif (UNIX)
         if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
-            target_link_libraries(dynarmic PUBLIC rt)
+            target_link_libraries(dynarmic PRIVATE rt)
         endif()
         target_sources(dynarmic PRIVATE backend/x64/exception_handler_posix.cpp)
     else()
@@ -363,20 +363,24 @@ endif()
 include(CreateDirectoryGroups)
 create_target_directory_groups(dynarmic)
 
-target_include_directories(dynarmic PUBLIC ..)
+target_include_directories(dynarmic PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/..>
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
+)
 set_target_properties(dynarmic PROPERTIES
     VERSION ${dynarmic_VERSION}
     SOVERSION ${dynarmic_VERSION_MAJOR}
 )
 target_compile_options(dynarmic PRIVATE ${DYNARMIC_CXX_FLAGS})
+# $<BUILD_INTERFACE:> required because of https://gitlab.kitware.com/cmake/cmake/-/issues/15415
 target_link_libraries(dynarmic
-    PUBLIC
+    PRIVATE
-        boost
+        $<BUILD_INTERFACE:boost>
-        fmt::fmt
+        $<BUILD_INTERFACE:fmt::fmt>
-        mp
+        $<BUILD_INTERFACE:mp>
         tsl::robin_map
-        xbyak
+        $<BUILD_INTERFACE:xbyak>
-        Zydis
+        $<BUILD_INTERFACE:Zydis>
         $<$<BOOL:DYNARMIC_USE_LLVM>:${llvm_libs}>
 )
 if (DYNARMIC_ENABLE_CPU_FEATURE_DETECTION)