Add missing <sys/select.h> include
This header is needed when types like fd_set are used. This fixes a
build issue occuring on the musl C library.
Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
[Thomas: better commit log.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
===================================================================
//// portable system includes //////////////////////////////////////
//// system dependent system includes //////////////////////////////
// low level I/O, where are prototypes and constants?