[CMake] Tweak FindOpus.cmake

cmake/FindOpus.cmake

@@ -1,23 +1,39 @@
 # - Try to find the Opus library
 # Once done this will define
 #
-#  OPUS_FOUND - system has Opus
-#  OPUS_INCLUDE_DIR - the OggOpus include directory
-#  OPUS_LIBRARY      - The Opus library
+#  Opus_FOUND - system has Opus
+#  Opus_INCLUDE_DIR - the OggOpus include directory
+#  Opus_LIBRARY      - The Opus library
 #
 # Also creates the imported Opus::opus target
 
-find_path(OPUS_INCLUDE_DIR opus/opus.h)
-find_library(OPUS_LIBRARY NAMES opus)
+# Try config mode first!
+find_package(Opus CONFIG QUIET) # Deliberately quiet, so we can handle the result
+if(Opus_FOUND)
+	if (TARGET Opus::opus)
+		# CONFIG mode succeeded
+		if(NOT Opus_INCLUDE_DIR)
+			get_target_property(Opus_INCLUDE_DIR Opus::opus INTERFACE_INCLUDE_DIRECTORIES)
+		endif()
+		if(NOT Opus_LIBRARY)
+			set(Opus_LIBRARY Opus::opus)
+		endif()
+		message(STATUS "Found Opus: ${Opus_INCLUDE_DIR}")
+		return()
+	endif()
+endif()
 
-mark_as_advanced(OPUS_INCLUDE_DIR OPUS_LIBRARY)
+find_path(Opus_INCLUDE_DIR opus/opus.h)
+find_library(Opus_LIBRARY NAMES opus)
+
+mark_as_advanced(Opus_INCLUDE_DIR Opus_LIBRARY)
 
 add_library(Opus::opus UNKNOWN IMPORTED)
 set_target_properties(Opus::opus
   PROPERTIES
-  IMPORTED_LOCATION "${OPUS_LIBRARY}"
-  INTERFACE_INCLUDE_DIRECTORIES "${OPUS_INCLUDE_DIR}"
+  IMPORTED_LOCATION "${Opus_LIBRARY}"
+  INTERFACE_INCLUDE_DIRECTORIES "${Opus_INCLUDE_DIR}"
 )
 
 include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(Opus REQUIRED_VARS OPUS_LIBRARY OPUS_INCLUDE_DIR)
+find_package_handle_standard_args(Opus REQUIRED_VARS Opus_LIBRARY Opus_INCLUDE_DIR)

lib/sound/CMakeLists.txt

@@ -66,7 +66,7 @@ else()
 	)
 	# opusfile.h includes "opus_multistream.h" instead of "opus/opus_multistream.h"
 	# so add "opus" subdirectory to fix that
-	set(OPUS_MULTISTREAM_DIR "${OPUS_INCLUDE_DIR}/opus")
+	set(OPUS_MULTISTREAM_DIR "${Opus_INCLUDE_DIR}/opus")
 	target_include_directories(opusfile PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/opusfile/include" "${OPUS_MULTISTREAM_DIR}")
 	target_link_libraries(opusfile PRIVATE Ogg::ogg Opus::opus)
 	include(CMakePushCheckState)
@@ -75,7 +75,7 @@ else()
 	include(CheckLibraryExists)
 	check_library_exists(m lrintf "" OP_HAVE_LIBM)
 	if(OP_HAVE_LIBM)
-		target_link_libraries(opusfile PRIVATE ${OGG_LIBRARY} ${OPUS_LIBRARY})
+		target_link_libraries(opusfile PRIVATE ${OGG_LIBRARY} ${Opus_LIBRARY})
 		list(APPEND CMAKE_REQUIRED_LIBRARIES "m")
 	endif()
 	check_symbol_exists(lrintf "math.h" OP_HAVE_LRINTF)