I'd never heard of genflags before until today, but it seems that it is generating potentially inadvisable CFLAGS, and some users may be following them (see the attached link). This is the output I get when running host2flags:
CFLAGS="-m64 -O3 -pipe -fPIC"
CXXFLAGS="-m64 -O3 -pipe -fPIC"
According to the amd64 technotes  the -m64 flag is irrelevant in normal usage, and could break anything that compiles things with -m32 internally, and people shouldn't use -fPIC globally.
Perhaps a warning should be issued if this is the case, or the output corrected?
yup, genflags is badly out of date.
When I wrote it all arches gave input on what the correct flags were for their systems.
It does badly need updating (a full rewrite actually), but I don't have time for it presently.
My longterm objective is to see what languages are provided in the latest releases again, and re-write all of genflags in it, also providing support for the many newer chips that have come out since genflags was first written.
If you could provide info on all of the newer /proc/cpuinfo for AMD64 machines, and the relevant CFLAGS to use, I'd appreciate it.
Mask message said:
# Robin H. Johnson <firstname.lastname@example.org> (20 Oct 2008)
# Masked for removal in 30 days (see bugs #120220, #137998, #170782)
# genflags should never have been born. Output needs to be specific per GCC
# version, and that's a big change.
so treecleaners removed it.