The larger size on Linux is because the binary itself contains the debug symbols. On Mac, they're in a separate .dSYM file from what I understand. See https://github.com/rust-lang/rust/issues/46034.
According to that thread, the size jump of the unstripped binary is probably from libstd being compiled with -C debuginfo=1 now.
According to that thread, the size jump of the unstripped binary is probably from libstd being compiled with -C debuginfo=1 now.