vanilla build of 7.7p1 release on linux/4.17 fails with gcc8 @ "/usr/bin/ld: unrecognized option '-Wl,-z,retpolineplt'"

[PGNet Dev]

hi

On 6/7/18 4:03 PM, Darren Tucker wrote:
> On 8 June 2018 at 07:09, PGNet Dev <pgnet.dev at gmail.com> wrote:
>> Verifying a report I just got pinged about, building vanilla openssh 7.7p1 on linux configures ok, but fails build around 'retpoline'
> [...]
>> Should the retpoline flag be getting added?  If so, what's needed to make LD happy with it?
> 
> configure checks to see if the linker accepts those flags, so my guess
> is that something is added later in configure that causes it to fail.
> I suggest looking at config.log to see what the actaul compiler
> messages are from these parts:
> 
> OSSH_CHECK_CFLAG_COMPILE([-mretpoline]) # clang
> OSSH_CHECK_LDFLAG_LINK([-Wl,-z,retpolineplt])
> 
> and the actual compiler output show up in config.log.
> 
> I wrote and tested this patch against the development versions of gcc
> and clang which was all that was available at the time, it's possible
> the released versions don't behave quite the same.

here's the complete config.log: https://paste.fedoraproject.org/paste/WtZP~Oe1~es2ddeqCBtCqQ

the 'fun' appears to start at line# 652

	gcc-8: error: unrecognized command line option '-mretpoline'; did you mean '-Wtrampolines'?

nooooo, no trampolines (is that a thing?) ;-)

at 1st quick look-thru, I'm just seeing that the flag failed, but not _why_.  yet.  looking closer now.

also, just fyi, during my testing I did try clang6 et al as well.  failed as well, with different/additional errors.  didn't spend any further time on it yet.