fix capitalisation on OpenAL's includes

fggl/audio/openal/CMakeLists.txt

@@ -2,10 +2,10 @@ find_package( OpenAL CONFIG )
 if ( NOT OpenAL_FOUND )
     # ubuntu/debian openal-soft package doesn't seem to have a config file
     # it's probably falling back to findOpenAL.cmake
-    message( STATUS "Using OpenAL-Soft config missing - falling back" )
+    message( STATUS "OpenAL-Soft config missing - falling back" )
     find_package( OpenAL REQUIRED )
-    target_link_libraries( fggl public ${OPENAL_LIBRARY} )
-    target_include_directories( fggl public ${OPENAL_INCLUDE_DIR} )
+    target_link_libraries( fggl PUBLIC ${OPENAL_LIBRARY} )
+    target_include_directories( fggl PUBLIC ${OPENAL_INCLUDE_DIR} )
 else()
     # we're using target-based
     message( STATUS "Using OpenAL-Soft config file" )