package/flac: enable building of libFLAC++
Besides libFLAC, also build libFLAC++ when C++ support is enabled.
Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 4937dda8935b671b6f2a9f42e1ebea9912c67351)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>