https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116730
--- Comment #26 from Hime Haieto <himehaieto at gmail dot com> --- (In reply to Jonathan Wakely from comment #22) > (In reply to Andreas Schwab from comment #15) > > Does it help to change the symlink creation rules in > > libstdc++-v3/src/libbacktrace/Makefile.am to use $(top_srcdir)/.. instead of > > ../../..? I think that should prevent VAPTH from interfering. > > > Yes, this was my thought too. I'll try it (on a machine that won't take a > year to build). It worked for me when I left the paths exactly as they were, but changed the link line to use $(LN_S) -f $< $@ That's basically how I got through the build before ever making this PR, though I did it in the generated makefile instead of the Makefile.am. In other words, the path leads to a valid build directory, but the same rule seems to be getting evaluated more than once, and the second time around the link fails since the link already exists, which -f fixes by forcing its recreation. The questions include why it's doing this in the first place, how it breaks in some cases but not others, etc.
