S2_6 missing host-cpu-c-abi.m4
Even in S2_6 lib-prefix.m4 has AC_REQUIRE(gl_HOST_CPU_C_ABI_32BIT). Yet there is no host-cpu-c-abi.m4 providing the gl_HOST_CPU_C_ABI_32BIT macro.
False alarm. That lib-prefix.m4 line comes from local patch ( #41758 ). It's not in S2_6 at the moment.
host-cpu-c-abi.m4 will be added by patch #41758 that needs it. Closing this one.