This fixes compilation with GCC >= 12.x, which is unhappy about the use
after free:
/home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/src/ccnl-relay.c: In function 'ccnl_fib_rem_entry':
/home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/src/ccnl-relay.c:916:16: error: pointer 'fwd' used after 'free' [-Werror=use-after-free]
916 | if (fwd->face) {
| ~~~^~~~~~
In file included from /home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/src/ccnl-relay.c:33:
/home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/../ccnl-riot/include/ccn-lite-riot.h:52:41: note: call to 'free' here
52 | #define ccnl_free(p) free(p)
| ^~~~~~~
/home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/src/ccnl-relay.c:910:13: note: in expansion of macro 'ccnl_free'
910 | ccnl_free(fwd);
| ^~~~~~~~~
/home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/src/ccnl-relay.c: In function 'ccnl_fib_rem_entry':
/home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/src/ccnl-relay.c:916:16: error: pointer 'fwd' used after 'free' [-Werror=use-after-free]
916 | if (fwd->face) {
| ~~~^~~~~~
In file included from /home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/src/ccnl-relay.c:33:
/home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-riot/include/ccn-lite-riot.h:52:41: note: call to free' here
52 | #define ccnl_free(p) free(p)
| ^~~~~~~
/home/maribu/Repos/software/RIOT/build/pkg/ccn-lite/src/ccnl-core/src/ccnl-relay.c:910:13: note: in expansion of macro 'ccnl_free'
910 | ccnl_free(fwd);
| ^~~~~~~~~
The definition of gettimeofday in pkg/ccn-lite leads to multiple definitions on platforms where gettimeofday is compiled in in newlib. Therefore, the gettimeofday function in pkg/ccn-lite is declared as weak symbol.
