core/memory.c: fix mmap usage in SIGSEGV handler (see issue #1429)
core/memory.c: fix mmap usage in SIGSEGV handler (see issue #1429)

See also:
https://github.com/snabbco/snabb/pull/1373 (73de63b)

SnabbCo/snabbswitch,alexandergall/snabbswitch,Igalia/snabb,SnabbCo/snabbswitch,eugeneia/snabb,eugeneia/snabb,snabbco/snabb,alexandergall/snabbswitch,Igalia/snabb,eugeneia/snabb,alexandergall/snabbswitch,SnabbCo/snabbswitch,alexandergall/snabbswitch,Igalia/snabb,alexandergall/snabbswitch,Igalia/snabb,snabbco/snabb,snabbco/snabb,eugeneia/snabb,Igalia/snabb,snabbco/snabb,snabbco/snabb,alexandergall/snabbswitch,alexandergall/snabbswitch,Igalia/snabb,alexandergall/snabbswitch,SnabbCo/snabbswitch,snabbco/snabb,snabbco/snabb,eugeneia/snabb,Igalia/snabb,Igalia/snabb,eugeneia/snabb,snabbco/snabb,eugeneia/snabb,eugeneia/snabb