[Bug lto/87076] -mpcu/-march not propagated through LTO bytecode (ice/segfault if arch flags do not match)

[kelledin at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87076

--- Comment #1 from Frank Schaefer <kelledin at gmail dot com> ---
Coming from PR87067: binutils suffers badly from this, because the testsuite
apparently honors $CFLAGS but intentionally ignores $LDFLAGS.  So even if an
end-user does the right thing and adds consistent "-march=..." to both CFLAGS
and LDFLAGS, this quirk brutally murders all the binutils LTO regression tests
on armv7 and similar.

For my part, I can get around this by adding my "-march=..." flags to $CC/$CXX,
but that's just gross.  +1 to auto-propagating these flags through the
bytecode.