test that environ gets deallocated on changes

Author: pvdrz

tests/compile-fail/environ-gets-deallocated.rs

@@ -0,0 +1,10 @@
+extern "C" {
+    static environ: *const *const u8;
+}
+
+fn main() {
+    let pointer = unsafe { environ };
+    let _x = unsafe { *pointer };
+    std::env::set_var("FOO", "BAR");
+    let _y = unsafe { *pointer }; //~ ERROR dangling pointer was dereferenced
+}