std.zig.system.NativeTargetInfo: restore symlink logic

This is a partial revert of the previous commit, fixing a regression on
Debian. However, the commit additionally improves the
detectAbiAndDynamicLinker function to read more than 1 byte at a time
when detecting a shebang line.
9f40f34501Andrew Kelley committed on 9/9/2022, 3:52:49 AMparentc668396
1 file changedLine totals unavailable