Anet is excluded from ppc64le because two tests in its test suite fail:
Tests for UDP processing:
Validate UDP checksum - UDP header checksum 32185 invalid, should be 33715 ERROR 0.000024000s
raised ANET.UDP.INVALID_UDP_PACKET : UDP header checksum 32185 invalid, should be 33715
Tests for IP processing:
Validate IP packet - Invalid IHL: 4 ERROR 0.000025000s
raised ANET.IPV4.INVALID_IP_PACKET : Invalid IHL: 4
I suspect an endianness bug in Libgnat, an incorrect value of System.Default_Bit_Order (in /usr/lib/gcc/*/*/adainclude/system.ads), but more investigation is needed to confirm this.
This bug appears to have been reported against 'rawhide' during the Fedora 26 development cycle.
Changing version to '26'.
This seems to be fixed in GCC 8.