Merge pull request #5772 from miri64/gnrc/feat/sock

Makefile.dep

Makefile.pseudomodules

sys/Makefile.include

sys/net/gnrc/Makefile

sys/net/gnrc/sock/Makefile

sys/net/gnrc/sock/gnrc_sock.c

sys/net/gnrc/sock/include/gnrc_sock_internal.h

sys/net/gnrc/sock/include/sock_types.h

sys/net/gnrc/sock/ip/Makefile

sys/net/gnrc/sock/ip/gnrc_sock_ip.c

sys/net/gnrc/sock/udp/Makefile

sys/net/gnrc/sock/udp/gnrc_sock_udp.c

tests/gnrc_sock_ip/Makefile

tests/gnrc_sock_ip/constants.h

tests/gnrc_sock_ip/main.c

tests/gnrc_sock_ip/stack.c

tests/gnrc_sock_ip/stack.h

tests/gnrc_sock_ip/tests/01-run.py

tests/gnrc_sock_udp/Makefile

tests/gnrc_sock_udp/constants.h