Add modifications needed for L4re in libstd

This commit adds the needed modifications to compile the std crate
for the L4 Runtime environment (L4Re).

A target for the L4Re was introduced in commit:
c151220a84e40b65e45308cc0f3bbea4466d3acf

In many aspects implementations for linux also apply for the L4Re
microkernel.

Two uncommon characteristics had to be resolved:
* L4Re has no network funktionality
* L4Re has a maximum stacksize of 1Mb for threads

Co-authored-by: Sebastian Humenda <sebastian.humenda@tu-dresden.de>

1 files changed, 6 insertions, 3 deletions

diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index 8e41fd009be..5ef98d24710 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -38,7 +38,10 @@ static ENV_LOCK: Mutex = Mutex::new();
 
 extern {
     #[cfg(not(target_os = "dragonfly"))]
-    #[cfg_attr(any(target_os = "linux", target_os = "emscripten", target_os = "fuchsia"),
+    #[cfg_attr(any(target_os = "linux",
+                   target_os = "emscripten",
+                   target_os = "fuchsia",
+                   target_os = "l4re"),
                link_name = "__errno_location")]
     #[cfg_attr(any(target_os = "bitrig",
                    target_os = "netbsd",
@@ -346,10 +349,10 @@ pub fn current_exe() -> io::Result<PathBuf> {
     }
 }
 
-#[cfg(target_os = "fuchsia")]
+#[cfg(any(target_os = "fuchsia", target_os = "l4re"))]
 pub fn current_exe() -> io::Result<PathBuf> {
     use io::ErrorKind;
-    Err(io::Error::new(ErrorKind::Other, "Not yet implemented on fuchsia"))
+    Err(io::Error::new(ErrorKind::Other, "Not yet implemented!"))
 }
 
 pub struct Env {