Local loopback:  Set the IFF_UP flags during initialization because the local loopback device is always up

Networking:  Fix network device name assignment logic for the case of the local loopback device.  There is only one local loopback network device and it is unnumbered

Compilation warning fixup

Signed-off-by: Anton D. Kachalov <mouse@yandex-team.ru>

Signed-off-by: Anton D. Kachalov <mouse@yandex-team.ru>

Kconfig: CONFIG_NET_MULTILINK and CONFIG_NET_MULTINIC must be support if the loopback device and any real network device are selected

Optional canned symtab inclusion to the build. When option CONFIG_LIBC_SYMTAB is selected and symbol table file libc/symtab/canned_symtab.inc is prepared then application can use system provided complete symbol table. The option has substantial effect on system image size. Mainly code/text. If loading of applications at runtime is not planned do not select this.  From Pavel Pisa.