[cmake] find TinyXML-2 without CMake config files

TinyXML-2 can be built with meson, which doesn't generate the CMake config files.

Author: Rechi

cmake/FindTinyXML2.cmake

@@ -0,0 +1,42 @@
+# FindTinyXML2
+# -----------
+# Finds the TinyXML2 library
+#
+# This will define the following variables:
+#
+# TINYXML2_FOUND - system has TinyXML2
+#
+# and the following imported targets:
+#
+#   tinyxml2::tinyxml2 - The UDEV library
+
+find_package(TinyXML2 CONFIG)
+
+if(TinyXML2_FOUND)
+  set(TINYXML2_FOUND TinyXML2_FOUND)
+elseif(NOT TinyXML2_FOUND)
+  find_package(PkgConfig)
+  if(PKG_CONFIG_FOUND)
+    pkg_check_modules(PC_TINYXML2 tinyxml2 QUIET)
+  endif()
+
+  find_path(TINYXML2_INCLUDE_DIR tinyxml2.h
+                                 PATHS ${PC_TINYXML2_INCLUDEDIR})
+  find_library(TINYXML2_LIBRARY NAMES tinyxml2
+                                PATHS ${PC_TINYXML2_LIBDIR})
+  set(TINYXML2_VERSION ${PC_TINYXML2_VERSION})
+
+  include(FindPackageHandleStandardArgs)
+  find_package_handle_standard_args(TinyXML2
+                                    REQUIRED_VARS TINYXML2_LIBRARY TINYXML2_INCLUDE_DIR
+                                    VERSION_VAR TINYXML2_VERSION)
+
+  if(TINYXML2_FOUND)
+    add_library(tinyxml2::tinyxml2 UNKNOWN IMPORTED)
+    set_target_properties(tinyxml2::tinyxml2 PROPERTIES
+                          IMPORTED_LOCATION "${TINYXML2_LIBRARY}"
+                          INTERFACE_INCLUDE_DIRECTORIES "${TINYXML2_INCLUDE_DIR}")
+  endif()
+
+  mark_as_advanced(TINYXML2_INCLUDE_DIR TINYXML2_LIBRARY)
+endif()