CMake: Fix Vorbis dependency handling

* Fix Vorbis not found for CMake < 3.17 (closes #530)
* Update FindVorbis module documentation
* Remove unused VorbisEnc.cmake
* Fix bug in SndFileConfig.cmake.in

Makefile.am

@@ -19,7 +19,7 @@ EXTRA_DIST = libsndfile.spec.in sndfile.pc.in Scripts/android-configure.sh \
 cmake_files = cmake/ClipMode.cmake cmake/FindFLAC.cmake \
 	cmake/CMakeAutoGen.cmake cmake/CMakeAutoGenScript.cmake \
 	cmake/FindOgg.cmake cmake/FindVorbis.cmake cmake/FindSndio.cmake \
-	cmake/FindSpeex.cmake cmake/FindSQLite3.cmake cmake/FindVorbisEnc.cmake \
+	cmake/FindSpeex.cmake cmake/FindSQLite3.cmake \
 	cmake/SndFileChecks.cmake cmake/TestInline.cmake \
 	cmake/TestLargeFiles.cmake cmake/TestInline.c.in \
 	cmake/FindOpus.cmake cmake/SndFileConfig.cmake.in

cmake/FindVorbis.cmake

@@ -1,9 +1,71 @@
-# - Find vorbisenc
+#[=======================================================================[.rst:
-# Find the native vorbisenc includes and libraries
+FindVorbis
-#
+----------
-#  VORBIS_INCLUDE_DIRS - where to find vorbis.h, etc.
+
-#  VORBIS_LIBRARIES    - List of libraries when using vorbis.
+Finds the native vorbis, vorbisenc amd vorbisfile includes and libraries.
-#  VORBIS_FOUND        - True if vorbis found.
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+This module provides the following imported targets, if found:
+
+``Vorbis::vorbis``
+  The Vorbis library
+``Vorbis::vorbisenc``
+  The VorbisEnc library
+``Vorbis::vorbisfile``
+  The VorbisFile library
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+This will define the following variables:
+
+``Vorbis_Vorbis_INCLUDE_DIRS``
+  List of include directories when using vorbis.
+``Vorbis_Enc_INCLUDE_DIRS``
+  List of include directories when using vorbisenc.
+``Vorbis_File_INCLUDE_DIRS``
+  List of include directories when using vorbisfile.
+``Vorbis_Vorbis_LIBRARIES``
+  List of libraries when using vorbis.
+``Vorbis_Enc_LIBRARIES``
+  List of libraries when using vorbisenc.
+``Vorbis_File_LIBRARIES``
+  List of libraries when using vorbisfile.
+``Vorbis_FOUND``
+  True if vorbis and requested components found.
+``Vorbis_Vorbis_FOUND``
+  True if vorbis found.
+``Vorbis_Enc_FOUND``
+  True if vorbisenc found.
+``Vorbis_Enc_FOUND``
+  True if vorbisfile found.
+
+Cache variables
+^^^^^^^^^^^^^^^
+
+The following cache variables may also be set:
+
+``Vorbis_Vorbis_INCLUDE_DIR``
+  The directory containing ``vorbis/vorbis.h``.
+``Vorbis_Enc_INCLUDE_DIR``
+  The directory containing ``vorbis/vorbisenc.h``.
+``Vorbis_File_INCLUDE_DIR``
+  The directory containing ``vorbis/vorbisenc.h``.
+``Vorbis_Vorbis_LIBRARY``
+  The path to the vorbis library.
+``Vorbis_Enc_LIBRARY``
+  The path to the vorbisenc library.
+``Vorbis_File_LIBRARY``
+  The path to the vorbisfile library.
+
+Hints
+^^^^^
+
+A user may set ``Vorbis_ROOT`` to a vorbis installation root to tell this module where to look.
+
+#]=======================================================================]
 
 if (Vorbis_Vorbis_INCLUDE_DIR)
 	# Already in cache, be silent
@@ -21,7 +83,7 @@ pkg_check_modules (PC_Vorbis_Vorbis QUIET vorbis)
 pkg_check_modules (PC_Vorbis_Enc QUIET vorbisenc)
 pkg_check_modules (PC_Vorbis_File QUIET vorbisfile)
 
-set (Vorbis_VERSION ${PC_VORBIS_VERSION})
+set (Vorbis_VERSION ${PC_Vorbis_Vorbis_VERSION})
 
 find_path (Vorbis_Vorbis_INCLUDE_DIR vorbis/codec.h
 	HINTS
@@ -82,29 +144,26 @@ find_library (Vorbis_File_LIBRARY
 
 include (FindPackageHandleStandardArgs)
 
-find_package_handle_standard_args (Vorbis_Vorbis
+if (Vorbis_Vorbis_LIBRARY AND Vorbis_Vorbis_INCLUDE_DIR AND Ogg_FOUND)
+    set (Vorbis_Vorbis_FOUND TRUE)
+endif ()
+
+if (Vorbis_Enc_LIBRARY AND Vorbis_Enc_INCLUDE_DIR AND Vorbis_Vorbis_FOUND)
+    set (Vorbis_Enc_FOUND TRUE)
+endif ()
+
+if (Vorbis_Vorbis_FOUND AND Vorbis_File_LIBRARY AND Vorbis_File_INCLUDE_DIR)
+    set (Vorbis_File_FOUND TRUE)
+endif ()
+
+find_package_handle_standard_args (Vorbis
 	REQUIRED_VARS
 		Vorbis_Vorbis_LIBRARY
 		Vorbis_Vorbis_INCLUDE_DIR
 		Ogg_FOUND
-	NAME_MISMATCHED
+	HANDLE_COMPONENTS
-	)
+	VERSION_VAR Vorbis_VERSION)
 
-find_package_handle_standard_args (Vorbis_Enc
-	REQUIRED_VARS
-		Vorbis_Enc_LIBRARY
-		Vorbis_Enc_INCLUDE_DIR
-		Vorbis_Vorbis_FOUND
-	NAME_MISMATCHED
-	)
-
-find_package_handle_standard_args (Vorbis_File
-	REQUIRED_VARS
-		Vorbis_File_LIBRARY
-		Vorbis_File_INCLUDE_DIR
-		Vorbis_Vorbis_FOUND
-	NAME_MISMATCHED
-	)
 
 if (Vorbis_Vorbis_FOUND)
 	set (Vorbis_Vorbis_INCLUDE_DIRS ${VORBIS_INCLUDE_DIR})
@@ -146,14 +205,6 @@ if (Vorbis_Vorbis_FOUND)
 
 endif ()
 
-find_package_handle_standard_args (Vorbis
-	REQUIRED_VARS
-		Vorbis_Vorbis_LIBRARY
-		Vorbis_Vorbis_INCLUDE_DIR
-		Ogg_FOUND
-	HANDLE_COMPONENTS
-	VERSION_VAR Vorbis_VERSION)
-
 mark_as_advanced (Vorbis_Vorbis_INCLUDE_DIR Vorbis_Vorbis_LIBRARY)
 mark_as_advanced (Vorbis_Enc_INCLUDE_DIR Vorbis_Enc_LIBRARY)
 mark_as_advanced (Vorbis_File_INCLUDE_DIR Vorbis_File_LIBRARY)

cmake/FindVorbisEnc.cmake

@@ -1,64 +0,0 @@
-# - Find vorbisenc
-# Find the native vorbisenc includes and libraries
-#
-#  VORBISENC_INCLUDE_DIRS - where to find vorbisenc.h, etc.
-#  VORBISENC_LIBRARIES    - List of libraries when using vorbisenc.
-#  VORBISENC_FOUND        - True if vorbisenc found.
-
-if (VORBISENC_INCLUDE_DIR)
-	# Already in cache, be silent
-	set (VORBISENC_FIND_QUIETLY TRUE)
-endif ()
-
-find_package (Vorbis QUIET)
-
-find_package (PkgConfig QUIET)
-pkg_check_modules (PC_VORBISENC QUIET vorbisenc)
-
-set (VORBISENC_VERSION ${PC_VORBISENC_VERSION})
-
-find_path (VORBISENC_INCLUDE_DIR vorbis/vorbisenc.h
-	HINTS
-		${PC_VORBISENC_INCLUDEDIR}
-		${PC_VORBISENC_INCLUDE_DIRS}
-		${VORBISENC_ROOT}
-	)
-
-find_library (VORBISENC_LIBRARY
-	NAMES
-		vorbisenc
-		vorbisenc_static
-		libvorbisenc
-		libvorbisenc_static
-	HINTS
-		${PC_VORBISENC_LIBDIR}
-		${PC_VORBISENC_LIBRARY_DIRS}
-		${VORBISENC_ROOT}
-	)
-
-# Handle the QUIETLY and REQUIRED arguments and set VORBISENC_FOUND
-# to TRUE if all listed variables are TRUE.
-include (FindPackageHandleStandardArgs)
-find_package_handle_standard_args (VorbisEnc
-	REQUIRED_VARS
-		VORBISENC_LIBRARY
-		VORBISENC_INCLUDE_DIR
-		VORBIS_FOUND
-	VERSION_VAR
-        VORBISENC_VERSION
-	)
-
-if (VORBISENC_FOUND)
-	set (VORBISENC_INCLUDE_DIRS ${VORBISENC_INCLUDE_DIR})
-	set (VORBISENC_LIBRARIES ${VORBISENC_LIBRARY} ${VORBIS_LIBRARIES})
-    if (NOT TARGET Vorbis::VorbisEnc)
-		add_library (Vorbis::VorbisEnc UNKNOWN IMPORTED)
-		set_target_properties (Vorbis::VorbisEnc PROPERTIES
-			INTERFACE_INCLUDE_DIRECTORIES "${VORBISENC_INCLUDE_DIR}"
-			IMPORTED_LOCATION "${VORBISENC_LIBRARY}"
-			INTERFACE_LINK_LIBRARIES Vorbis::Vorbis
-		)
-	endif ()
-endif ()
-
-mark_as_advanced (VORBISENC_INCLUDE_DIR VORBISENC_LIBRARY)

cmake/SndFileConfig.cmake.in

@@ -11,7 +11,7 @@ include (CMakeFindDependencyMacro)
 
 if (SndFile_WITH_EXTERNAL_LIBS AND NOT @BUILD_SHARED_LIBS@)
 	find_dependency (Ogg 1.3)
-	find_dependency (VorbisEnc)
+	find_dependency (Vorbis)
 	find_dependency (FLAC)
 	find_dependency (Opus)
 endif ()