Enabling LTO for target libraries (e.g., libgo, libstdc++)

[Joseph Myers]

On Fri, 25 Jan 2019, Nikhil Benesch wrote:

> I am attempting to convince GCC to build target libraries with link-time
> optimizations enabled. I am primarily interested in libgo, but this discussion

Note that as far as I know issues with host-dependencies of LTO bytecode 
(bug 41526) may still exist, so this wouldn't work with Canadian cross 
compilers.

> I have a simple patch to the top-level configure.ac that resolves the issue by
> teaching the build system to use the gcc-ar and gcc-ranlib wrappers which were
> built earlier and know how to pass the linker plugin to the underlying ar/ranlib
> commands. The patch is small enough that I've included it at the end of this
> email.

Will those wrappers properly wrap round tools for the target that were 
configured using --with-build-time-tools?

-- 
Joseph S. Myers
joseph@codesourcery.com