Instead of linking directly to the rust crate, try to figure out the location
and name of the library from the file name, then call gcc with appropriate -L,
-l flags. This will allow dynamic linking to be more forgiving about where it
loads the library from at runtime - currently a stage3 compiler can't run
correctly from the stage0 directory. Only tested on Linux. Fingers crossed.
The meta items within a crate's link attribute are used in linkage:
#[link(name = "std",
vers = "1.0",
custom = "whatever")];
Name and vers are treated specially, and everything else is hashed together
into the crate meta hash.
Issue #487
