Include statements missing in utils.h and utils.c

[dariuszSki]

When I was cross-compiling Teltonika v6.9 with ZET v0.17.36, I got two errors. I bypassed them by adding these:

1. #include <sys/wait.h> to this file ~/ziti-tunnel-sdk-c/programs/ziti-edge-tunnel/netif_driver/linux/utils.c
2. #include <stdarg.h> to this file ~/ziti-tunnel-sdk-c/programs/ziti-edge-tunnel/netif_driver/linux/utils.h

Errors seen:

In file included from /home/ubuntu/ziti-tunnel-sdk-c/programs/ziti-edge-tunnel/netif_driver/linux/resolvers.c:30:0:
/home/ubuntu/ziti-tunnel-sdk-c/programs/ziti-edge-tunnel/netif_driver/linux/utils.h:19:58: error: unknown type name 'va_list'
 int run_command_va(bool log_nonzero_ec, const char* cmd, va_list args);

And

CMakeFiles/ziti-edge-tunnel.dir/netif_driver/linux/utils.c.o: In function `run_command_va':
/home/ubuntu/ziti-tunnel-sdk-c/programs/ziti-edge-tunnel/netif_driver/linux/utils.c:33: undefined reference to `WEXITSTATUS