https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97183
--- Comment #3 from Jim Wilson <wilson at gcc dot gnu.org> --- I installed Ubuntu 16.04 on an old laptop so I can directly reproduce the build failure. Checking for the zstd version looks like the easier patch. Checking for specific macros and functions might be better, but what do we do with the info? I'm not familiar with zstd or the lto-compress.c code, and it doesn't look like we can easily change it to not use certain macros/functions when they don't exist. Checking for half a dozen macros/functions and disabling all of the code if one or more is missing seems silly. Though looking at this, as Kito pointed out, it appears that ZSTD_getFrameContentSize() is the most recently added function that we are using, so maybe we only need to check for that one. That was added in version 1.3.0. Or we can check for the 1.3.0 version which seems simpler. I do know that version 1.3.3 of zstd works as this is what Ubuntu 18.04 has. I haven't tried the versions 1.3.[012].
