+++ This bug was initially created as a clone of Bug #294178 +++ There are some AMD Sempron CPUs with an athlon64 core but no actual x86_64 support. Working CFLAGS for those CPUs are e.g. "-march=i686 -mtune=athlon64 -m32" The current configure setup in mythtv-0.22_p24255.ebuild does not account for this, configuring --tune=athlon64 which defaults x86_64 build. The (configure test) compile then fails for such CPUs with the venerable "compile cannot create excutables" error. Maybe mythtv could feature an 64bit/32bit USE flag like this? if use 32bit; then myconf="${myconf} --extra-cxxflags=-m32" fi
mtune=athlon64 implies 64 bit instructions in gcc
(In reply to comment #1) > mtune=athlon64 implies 64 bit instructions in gcc That may well be, however I assure you that the combination of "-march=athlon64 -m32" does work fine on those CPUs I am talking about. Those _are_ athlon64 (k8) cores but they only do 32bit. They are _not_ athlon-xp (k7) cores (which would be the "next step down" in gcc -march targets). They are/were low-power chips oringinally designed for laptops but later released for PCs as cheap, low-power solution ideally suited for HTPC usage. See: http://en.wikipedia.org/wiki/Sempron#Models_for_Socket_754 And I'd wager they will be encountered in mythtv boxes and it would be nice if the ootb ebuild would support them. Isn't that what the gcc -m32 switch is all about? Wether that is done via USE flag or based on CHOST or differently is entirely up to your tastes, I'm just telling you but the USE flag version does work fine (if you actually do '${myconf} --extra-cflags=-m32 --extra-cxxflags=-m32' not just cxx as I wrote above.)
Attach the output of "gcc -E -dM - < /dev/null -march=native".
Also attach the output of "gcc -Q --help=target -march=native"
Created attachment 235533 [details] gcc_Q.txt = gcc -Q --help=target -march=native
Created attachment 235535 [details] gcc_E.txt =gcc -E -dM - < /dev/null -march=native
The computer I had this problem with died a while ago, so personally I'd say You can close this. Although I still think being able to force 32bits would be an enhancement to the ebuilds.
Well now with x32 as a valid arch this is real. It will be fixed in 0.25.1
This should be solved in 0.25.1 and newer.
