Unique names 3/6

Unique names 3/6

Give symbols of libxt matches unique names (2/3).

Adds unique prefixes to all functions (most of them - especially the hook
functions) so that debugging programs can unambiguously map a symbol to an
address. Also unifies the names of the xtables_match/xtables_target structs,
(based upon libxt_connmark.c/libip6t_*.c).

Signed-off-by: Jan Engelhardt <jengelh@gmx.de>