error

rustc src/lib.rs -o idris/idrisfs.o --crate-type=lib --emit=obj

Undefined symbols for architecture x86_64:
  "___morestack", referenced from:
      _sizeof_int in idrisfs.o
      sizeof_int::__rust_abi in idrisfs.o
      mem::size_of::h1f2d9faff57bec09oaa::v0.0 in idrisfs.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
FAILURE: gcc -O2  -fwrapv -fno-strict-overflow -I. ./idrisfs.o  -x c  /var/folders/_t/g72k9vzd30b5svvyd1nxpwp40000gn/T/idris5178 -L/Users/sven/Library/Haskell/ghc-7.6.3/lib/idris-0.9.12/share/rts -lidris_rts -lgmp -lpthread -I/Users/sven/Library/Haskell/ghc-7.6.3/lib/idris-0.9.12/share/rts -I. -I/Users/sven/Library/Haskell/ghc-7.6.3/lib/idris-0.9.12/share/prelude -I/Users/sven/Library/Haskell/ghc-7.6.3/lib/idris-0.9.12/share/base   -o /var/folders/_t/g72k9vzd30b5svvyd1nxpwp40000gn/T/idris5176
/bin/sh: /var/folders/_t/g72k9vzd30b5svvyd1nxpwp40000gn/T/idris5176: No such file or directory

idrisfs.hs

module Main

-- %dynamic "./../target/x86_64-apple-darwin/lib/libidrisfs-ba8d5852-0.0.dylib"

%include C "idrisfs.h"
%link C "idrisfs.o"

getSizeInt : IO Int
getSizeInt = mkForeign (FFun "sizeof_int" [] FInt)

main : IO ()
main = do
  x <- getSizeInt
  putStrLn (show x)

idrisfs.rs

#![crate_id = "idrisfs"]
#![deny(missing_doc)]

//! Documentation goes here.

/// Returns the number of bytes in an int.
#[no_mangle]
pub extern "C" fn sizeof_int() -> int {
    std::mem::size_of::<int>() as int
}