Overhaul CMake build

cmake/tinyxml2-config.cmake

@@ -0,0 +1,57 @@
+cmake_minimum_required(VERSION 3.15)
+
+set(tinyxml2_known_comps static shared)
+set(tinyxml2_comp_static NO)
+set(tinyxml2_comp_shared NO)
+foreach (tinyxml2_comp IN LISTS ${CMAKE_FIND_PACKAGE_NAME}_FIND_COMPONENTS)
+    if (tinyxml2_comp IN_LIST tinyxml2_known_comps)
+        set(tinyxml2_comp_${tinyxml2_comp} YES)
+    else ()
+        set(${CMAKE_FIND_PACKAGE_NAME}_NOT_FOUND_MESSAGE
+            "tinyxml2 does not recognize component `${tinyxml2_comp}`.")
+        set(${CMAKE_FIND_PACKAGE_NAME}_FOUND FALSE)
+        return()
+    endif ()
+endforeach ()
+
+if (tinyxml2_comp_static AND tinyxml2_comp_shared)
+    set(${CMAKE_FIND_PACKAGE_NAME}_NOT_FOUND_MESSAGE
+        "tinyxml2 `static` and `shared` components are mutually exclusive.")
+    set(${CMAKE_FIND_PACKAGE_NAME}_FOUND FALSE)
+    return()
+endif ()
+
+set(tinyxml2_static_targets "${CMAKE_CURRENT_LIST_DIR}/tinyxml2-static-targets.cmake")
+set(tinyxml2_shared_targets "${CMAKE_CURRENT_LIST_DIR}/tinyxml2-shared-targets.cmake")
+
+macro(tinyxml2_load_targets type)
+    if (NOT EXISTS "${tinyxml2_${type}_targets}")
+        set(${CMAKE_FIND_PACKAGE_NAME}_NOT_FOUND_MESSAGE
+            "tinyxml2 `${type}` libraries were requested but not found.")
+        set(${CMAKE_FIND_PACKAGE_NAME}_FOUND FALSE)
+        return()
+    endif ()
+    include("${tinyxml2_${type}_targets}")
+endmacro()
+
+if (tinyxml2_comp_static)
+    tinyxml2_load_targets(static)
+elseif (tinyxml2_comp_shared)
+    tinyxml2_load_targets(shared)
+elseif (DEFINED tinyxml2_SHARED_LIBS AND tinyxml2_SHARED_LIBS)
+    tinyxml2_load_targets(shared)
+elseif (DEFINED tinyxml2_SHARED_LIBS AND NOT tinyxml2_SHARED_LIBS)
+    tinyxml2_load_targets(static)
+elseif (BUILD_SHARED_LIBS)
+    if (EXISTS "${tinyxml2_shared_targets}")
+        tinyxml2_load_targets(shared)
+    else ()
+        tinyxml2_load_targets(static)
+    endif ()
+else ()
+    if (EXISTS "${tinyxml2_static_targets}")
+        tinyxml2_load_targets(static)
+    else ()
+        tinyxml2_load_targets(shared)
+    endif ()
+endif ()