Use openlibm's fenv.h

include/fenv.h

@@ -0,0 +1,2 @@
+#include <openlibm_fenv.h>
+#undef I

src/header/float/mod.rs

@@ -1,7 +1,7 @@
 //! float.h implementation for Redox, following
 //! http://pubs.opengroup.org/onlinepubs/7908799/xsh/float.h.html
 
-use header::fenv::{fegetround, FE_TONEAREST};
+use header::_fenv::{fegetround, FE_TONEAREST};
 use platform::types::*;
 
 pub const FLT_RADIX: c_int = 2;

src/header/mod.rs

@@ -5,7 +5,7 @@ pub mod ctype;
 pub mod dirent;
 pub mod errno;
 pub mod fcntl;
-pub mod fenv;
+pub mod _fenv;
 pub mod float;
 pub mod fnmatch;
 pub mod getopt;