/cc @grahamc @edolstra

This is weird. Shouldn't this be something handled by gcc / libstdc++?

This is weird. Shouldn't this be something handled by gcc / libstdc++?

Yeah I would expect that to happen, but it doesn't look like it has. At least boost's atomic, which uses this symbol should have this check. Most platforms have hardware atomics, but arm32 does not so it needs to use the software version. It is probably necessary for PPC too.

Other projects like:

• KDE: libatomic, provides a software implementation of atomic built-ins, when needed
• Mesa: disk cache: Link with -latomic if necessary
• Protobuf: Link to libatomic when necessary (eg. on armv6l)

do this too.

/cc @lopsided98

Came across this issue while trying to package 2.3.10 Nix, and after backporting the commit, turns out, it never worked! $LIBS has not been looked at since Automake was removed in 2014, in commit 0c6d62c! Adding @LIBS@ to the LDFLAGS in the Makefile.config.in seems to have made it work, but feels a bit hacky (I don't entirely know what the interaction of the custom build system is with how autoconf does things by default..)