Trick the linker into not doing unncessary work searching for optimised
libraries that are not present, by symlinking the directories where
optimised libs would be to the main lib dir.
This reduces the ENOENT of git-annex init by about 1/2. The linker always
finds the files where it looks first time now. I have not looked at what
the wall clock speedup might be, it's probably rather small.
If a x86-64-v5 comes to be, the list will need to be extended. And there
may be other directories used on some machines that I have missed. Not done
for arm64 yet, or any uncommon architectures.
Sponsored-by: Dartmouth College's Datalad project
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