It appears that when building portable code, the ax_gcc_archflag.m4 macro clears -mcpu for almost every arch except powerpc:
https://github.com/libffi/libffi/blob/master/m4/ax_gcc_archflag.m4#L241 case $host_cpu in i*86|x86_64*|amd64*) flag_prefixes="$flag_prefixes -mcpu= -m";; esac The fact that PowerPC is excluded must result in m4 passing the “-mcpu=“ flag matching the buildbot’s CPU, and breaks everything older than the buildbot. This must happen with any build that uses this ax_gcc_archflag.m4 macro. I wonder why powerpc* is excluded? Seems like this line should rather be: case $host_cpu in i*86|x86_64*|powerpc*|amd64*) flag_prefixes="$flag_prefixes -mcpu= -m";; esac Ken PS. Although I did not as yet sort out getting the “experimental” packages (I keep getting an error when I try to use that option), building libffi in a couple of minutes on the local machine and installing that of course works easily. — K > On Nov 2, 2021, at 2:01 PM, John Paul Adrian Glaubitz > <[email protected]> wrote: > > On 11/2/21 21:59, Cameron MacPherson wrote: >> i got the 3.4.2-3+ports package after apt upgrade -t experimental and there >> are no illegal instructions > > As I expected. The build log didn't have any traces of "-mcpu=power8". > > Adrian > > -- > .''`. John Paul Adrian Glaubitz > : :' : Debian Developer - [email protected] > `. `' Freie Universitaet Berlin - [email protected] > `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913 >
