This reverts commit ce2f74df2cade57e74c235292c8b074281903e71.
Doubles are treated as -darwin here, to provide some consistency.
There is some ambiguity between “x86_64-darwin” and “i686-darwin”
which could refer to binaries linked between iOS simulator or real
macOS binaries. useiOSPrebuilt can be used to determine which to use,
however.
d059185bad