Emerald: Always have RUST_BACKTRACE=full

since we don't have environment variables yet, this makes it easy to debug

Author: Amjad50

library/std/src/sys/pal/emerald/os.rs

@@ -175,7 +175,10 @@ pub fn env() -> Env {
     panic!("not supported on this platform")
 }
 
-pub fn getenv(_: &OsStr) -> Option<OsString> {
+pub fn getenv(str: &OsStr) -> Option<OsString> {
+    if str == "RUST_BACKTRACE" {
+        return Some("full".into());
+    }
     None
 }