GDB 8.3.1 gdbserver linker error: needs -lrt

[Paul Smith]

On Fri, 2020-01-31 at 09:44 +0200, Eli Zaretskii wrote:
> > From: Simon Marchi <simark@simark.ca>
> > Date: Thu, 30 Jan 2020 17:49:59 -0500
> > 
> > > > That would work around the problem, but if you want to fix it
> > > > for good, for all users in the same situation, then it would
> > > > probably require a patch to configure.ac, to add "-lrt" to LIBS
> > > > when needed.
> > > 
> > > Yes, definitely... that's why I posted the message :).
> 
> Any reason why we don't use pkg-config for finding out these
> dependencies?

I'm not sure how pkg-config helps in this situation... isn't pkg-config 
used for obtaining correct options for using another package?

In this case, we need a new library to link gdbserver directly, not
because of some other package that gdbserver depends on, so we don't
have a package that might contain a pkg-config we could use.

Maybe you mean, a pkg-config for libstdc++ static linking?  I'm not
sure GCC installs such a thing.

I'm pretty sure there are a LOT of configure.ac files out there that
search for -lrt that could be used as.  It's just that in this case we
didn't realize we needed it, because (a) it's needed by libstdc++.a but
probably not if you dynamically link libstdc++ (becase the .so probably
links librt.so) and (b) it's only needed with older GNU libc; I think
newer versions of GNU libc have moved clock_gettime etc. into the
normal library and -lrt is obsolete.