This causes libstore, libexpr, libfetchers, and libutil to be linked
with -Wl,--whole-archive to executables, when building statically.
libstore for the store backends, libexpr for the primops, libfetchers
for the fetcher backends I assume(?), and libutil for the nix::logger
initializer (which notably shows in pre-main constructors when HOME is
not owned by the user. cursed.).
This workaround should be removed when #359 is fixed.
Fixes#306.
Change-Id: Ie9ef0154e09a6ed97920ee8ab23810ca5e2de84c