cmake - fix missing xml.lib in debug builds #7413

After 5d56025 we were using `LibXml2::LibXml2` instead of `LIBXML2_LIBRARIES` for linking, but this target was missing debug variants leading to issues during linking.

cmake/FindLibXml2.cmake

@@ -5,9 +5,8 @@
 # If input variables are not specified, try to find LibXml2 config.
 # Input variables could also be provided as environment variables.
 #
-# Output variables:
-# - `LIBXML2_INCLUDE_DIR`
-# - `LIBXML2_LIBRARIES`
+# Output targets:
+# - `LibXml2::LibXml2`
 #
 
 # To avoid cyclic calls to this file
@@ -27,23 +26,22 @@ if((NOT LIBXML2_INCLUDE_DIR AND NOT LIBXML2_LIBRARIES))
     else()
         message(STATUS "Found LibXml2 config: ${LibXml2_DIR}")
     endif()
-
-    if(TARGET LibXml2::LibXml2)
-        # Config mode already gives us the target
-        set(LIBXML2_LIBRARIES LibXml2::LibXml2)
-        get_target_property(LIBXML2_INCLUDE_DIR LibXml2::LibXml2 INTERFACE_INCLUDE_DIRECTORIES)
-    else()
-        # Module mode (Ubuntu)
-        set(LIBXML2_LIBRARIES ${LibXml2_LIBRARIES})
-        set(LIBXML2_INCLUDE_DIR ${LibXml2_INCLUDE_DIRS})
-    endif()
 else()
     find_package(LibXml2 REQUIRED)
+    if(MSVC)
+        # Unset `IMPORTED_LOCATION` and set it manually.
+        set_property(TARGET LibXml2::LibXml2 PROPERTY IMPORTED_LOCATION)
+        get_release_variant(LIBXML2_RELEASE_LIB "${LIBXML2_LIBRARIES}" "d")
+        get_debug_variant(LIBXML2_DEBUG_LIB "${LIBXML2_LIBRARIES}" "d")
+        set_target_properties(LibXml2::LibXml2
+            PROPERTIES
+            IMPORTED_CONFIGURATIONS "Release;Debug"
+            IMPORTED_LOCATION_RELEASE "${LIBXML2_RELEASE_LIB}"
+            IMPORTED_LOCATION_DEBUG "${LIBXML2_DEBUG_LIB}"
+        )
+    endif()
 endif()
 
-if(MSVC AND NOT LibXml2_DIR)
-    add_debug_variants(LIBXML2_LIBRARIES "${LIBXML2_LIBRARIES}" d)
-endif()
 
 # Restore module path.
 list(PREPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR})