LTO on Windows now working

[Noel Grandin]

On 2020/09/23 3:49 pm, Tor Lillqvist wrote:
> By the way, did you manage to get all external libraries to get built using LTO, too? Or just what goes into our merged 
> library? As far as I see, we use gb_LTOFLAGS only in three ExternalProject_foo.mk files. Should it be used in them all? 
> Should we append gb_LTOFLAGS to CC and CXX instead of keeping it separate?
> 

No, just the merged library. Would be nice to use it in externals too, but that would probably require fiddling with the 
various external build systems to pass in the necessary flags and workaround the consequent bugs.

Probably only worth doing for things that show up in profiles (icu comes to mind)