Add SGX target

Author: Jethro Beekman

src/lib.rs

@@ -158,12 +158,15 @@ cfg_if! {
         pub type uintptr_t = usize;
         pub type ssize_t = isize;
 
+        #[cfg(not(target_env = "sgx"))]
         pub enum FILE {}
+        #[cfg(not(target_env = "sgx"))]
         pub enum fpos_t {} // TODO: fill this out with a struct
 
         pub const INT_MIN: c_int = -2147483648;
         pub const INT_MAX: c_int = 2147483647;
 
+        #[cfg(not(target_env = "sgx"))]
         extern {
             pub fn isalnum(c: c_int) -> c_int;
             pub fn isalpha(c: c_int) -> c_int;
@@ -284,7 +287,7 @@ cfg_if! {
 
         // These are all inline functions on android, so they end up just being entirely
         // missing on that platform.
-        #[cfg(not(target_os = "android"))]
+        #[cfg(not(any(target_os = "android", target_env = "sgx")))]
         extern {
             pub fn abs(i: c_int) -> c_int;
             pub fn atof(s: *const c_char) -> c_double;
@@ -314,6 +317,9 @@ cfg_if! {
     } else if #[cfg(unix)] {
         mod unix;
         pub use unix::*;
+    } else if #[cfg(target_env = "sgx")] {
+        mod sgx;
+        pub use sgx::*;
     } else {
         // Unknown target_family
     }

src/sgx.rs

@@ -0,0 +1,3 @@
+pub type c_char = i8;
+pub type c_long = i64;
+pub type c_ulong = u64;