Makefile.am had a reference to it but it none of the sources included it.
Tested: "make dist" works again after this patchset is applied.
Fixes: 2ea8857effb833615b16d10fc7a19a7104c19e13
test_dhcp6_client_SOURCES = \
src/systemd/sd-dhcp6-client.h \
test_dhcp6_client_SOURCES = \
src/systemd/sd-dhcp6-client.h \
- src/libsystemd-network/dhcp6-icmp6.h \
src/libsystemd-network/dhcp6-internal.h \
src/libsystemd-network/test-dhcp6-client.c
src/libsystemd-network/dhcp6-internal.h \
src/libsystemd-network/test-dhcp6-client.c