meson: no longer pass -Wl,--no-undefined explicitly

to make it possible to build n-dhcp4 with clang and ASan.

-Wl,--no-undefined is still passed by meson by default unless -Db_lundef
is set to false explictily:
mesonbuild/meson#764

To get it to work the c-siphash submodule has to be bumped to at least
c-util/c-siphash@203347c
as well but it should probably be delayed until the next release or
something like that.

Signed-off-by: Evgeny Vereshchagin <evvers@ya.ru>

src/meson.build

@@ -44,7 +44,6 @@ libndhcp4_shared = shared_library(
         soversion: 0,
         link_depends: libndhcp4_symfile,
         link_args: [
-                '-Wl,--no-undefined',
                 '-Wl,--version-script=@0@'.format(libndhcp4_symfile)
         ],
 )