net-mgmt/riemann-c-client: Fix build

libtool: link: cc -shared -fPIC -DPIC lib/riemann/.libs/libriemann_client_gnutls_la-_private.o lib/riemann/.libs/libriemann_client_gnutls_la-client.o lib/riemann/client/.libs/libriemann_client_gnutls_la-socket.o lib/riemann/client/.libs/libriemann_client_gnutls_la-tcp.o lib/riemann/client/.libs/libriemann_client_gnutls_la-tls.o lib/riemann/client/.libs/libriemann_client_gnutls_la-udp.o lib/riemann/.libs/libriemann_client_gnutls_la-event.o lib/riemann/.libs/libriemann_client_gnutls_la-message.o lib/riemann/.libs/libriemann_client_gnutls_la-attribute.o lib/riemann/.libs/libriemann_client_gnutls_la-query.o lib/riemann/.libs/libriemann_client_gnutls_la-communicate.o lib/riemann/proto/.libs/libriemann_client_gnutls_la-riemann.pb-c.o -L/usr/local/lib -lprotobuf-c -lgnutls -O2 -fstack-protector-strong -Wl,--version-script -Wl,./lib/riemann/libriemann.ver -fstack-protector-strong -Wl,-soname -Wl,libriemann-client-gnutls.so.11 -o lib/.libs/libriemann-client-gnutls.so.11.1.1
ld: error: version script assignment of 'RIEMANN_C_2.0' to symbol 'riemann_event_init' failed: symbol not defined
cc: error: linker command failed with exit code 1 (use -v to see invocation)
gmake[1]: * [Makefile:788: lib/libriemann-client-gnutls.la] Error 1
gmake: * [Makefile:592: all] Error 2

> Compilation failed unexpectedly.

Try to set MAKE_JOBS_UNSAFE=yes and rebuild before reporting the failure to
the maintainer.

• Error code 1

Reference: https://pkg-status.freebsd.org/beefy18/data/main-amd64-default/p46b3743b8469_s3a4b04e82df/logs/riemann-c-client-2.1.1_1.log

		https://pkg-status.freebsd.org/beefy16/data/133amd64-default/46b3743b8469/logs/riemann-c-client-2.1.1_1.log

Approved by: portmgr (blanket)