move to new build system

cmake/libraries/ogg.cmake

@@ -0,0 +1,30 @@
+if(PROJECT_ENABLE_OGG)
+  if(PROJECT_BUILD)
+    find_package(Ogg ${OGG_VERSION} REQUIRED)
+
+    add_definitions(-DPROJECT_ENABLE_OGG)
+
+    include_directories(BEFORE SYSTEM
+      ${OGG_INCLUDE_DIRS}
+    )
+
+    link_libraries(
+      Ogg::ogg
+    )
+  elseif(NOT PROJECT_IS_MINGW OR CMAKE_HOST_WIN32)
+    ExternalProject_Add(ogg_project
+      PREFIX external
+      URL ${PROJECT_3RD_PARTY_DIR}/ogg-v${OGG_VERSION}.tar.gz
+      URL_HASH SHA256=f6f1b04cfa4e98b70ffe775d5e302d9c6b98541f05159af6de2d6617817ed7d6
+      LIST_SEPARATOR |
+      CMAKE_ARGS ${PROJECT_EXTERNAL_CMAKE_FLAGS}
+        -DBUILD_SHARED_LIBS=${PROJECT_BUILD_SHARED_LIBS}
+        -DBUILD_STATIC_LIBS=ON
+    )
+
+    set(PROJECT_DEPENDENCIES 
+      ${PROJECT_DEPENDENCIES}
+      ogg_project
+    )
+  endif()
+endif()