Detect utf8cpp by header if cmake config is not found (taglib#1217)

CMakeLists.txt

@@ -149,18 +149,33 @@ if(TRACE_IN_RELEASE)
 endif()
 
 find_package(utf8cpp QUIET)
-if(NOT utf8cpp_FOUND)
- if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/utfcpp/CMakeLists.txt)
- add_subdirectory("3rdparty/utfcpp")
- message(STATUS "Using utfcpp from ${utf8cpp_SOURCE_DIR}")
+if(utf8cpp_FOUND)
+ message(STATUS "Using utfcpp ${utf8cpp_VERSION} from ${utf8cpp_CONFIG}")
+else()
+ find_path(utf8cpp_INCLUDE_DIR NAMES utf8.h PATH_SUFFIXES utf8cpp
+ DOC "utf8cpp include directory")
+ mark_as_advanced(utf8cpp_INCLUDE_DIR)
+ include(FindPackageHandleStandardArgs)
+ find_package_handle_standard_args(utf8cpp REQUIRED_VARS utf8cpp_INCLUDE_DIR)
+ if(utf8cpp_FOUND)
+ set(utf8cpp_INCLUDE_DIRS "${utf8cpp_INCLUDE_DIR}")
+ if(NOT TARGET utf8::cpp)
+ add_library(utf8::cpp INTERFACE IMPORTED)
+ set_target_properties(utf8::cpp PROPERTIES
+ INTERFACE_INCLUDE_DIRECTORIES "${utf8cpp_INCLUDE_DIR}")
+ endif()
+ message(STATUS "Using utfcpp from ${utf8cpp_INCLUDE_DIR}")
  else()
- message(FATAL_ERROR
- "utfcpp not found. Either install package (probably utfcpp, utf8cpp, or libutfcpp-dev) "
- "or fetch the git submodule using\n"
- "git submodule update --init")
+ if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/utfcpp/CMakeLists.txt)
+ add_subdirectory("3rdparty/utfcpp")
+ message(STATUS "Using utfcpp from ${utf8cpp_SOURCE_DIR}")
+ else()
+ message(FATAL_ERROR
+ "utfcpp not found. Either install package (probably utfcpp, utf8cpp, or libutfcpp-dev) "
+ "or fetch the git submodule using\n"
+ "git submodule update --init")
+ endif()
  endif()
-else()
- message(STATUS "Using utfcpp ${utf8cpp_VERSION} from ${utf8cpp_CONFIG}")
 endif()
 
 add_subdirectory(taglib)