Rollup merge of rust-lang#66091 - Wind-River:master_xyz, r=cramertj

Implemented the home_dir for VxWorks

Use HOME's value if it is set;
otherwise return NONE.

src/libstd/sys/vxworks/os.rs

@@ -287,7 +287,8 @@ pub fn temp_dir() -> PathBuf {
 }
 
 pub fn home_dir() -> Option<PathBuf> {
-    None
+    crate::env::var_os("HOME").or_else(|| None
+    ).map(PathBuf::from)
 }
 
 pub fn exit(code: i32) -> ! {