Add -Zunstable-options instead of feature

src/test/run-make-fulldeps/foreign-exceptions/foo.rs

@@ -2,8 +2,6 @@
 // are caught by catch_unwind. Also tests that Rust panics can unwind through
 // C++ code.
 
-// For linking libstdc++ on MinGW
-#![cfg_attr(all(windows, target_env = "gnu"), feature(native_link_modifiers))]
 #![feature(c_unwind)]
 
 use std::panic::{catch_unwind, AssertUnwindSafe};

src/test/run-make-fulldeps/tools.mk

@@ -117,10 +117,10 @@ else
 	# that it is compiled with the expectation that pthreads is dynamically
 	# linked as a DLL and will fail to link with a statically linked libpthread.
 	#
-	# So we end up with the following hack: we link use static-nobundle to only
+	# So we end up with the following hack: we link use static:-bundle to only
 	# link the parts of libstdc++ that we actually use, which doesn't include
 	# the dependency on the pthreads DLL.
-	EXTRARSCXXFLAGS := -l static:-bundle=stdc++
+	EXTRARSCXXFLAGS := -l static:-bundle=stdc++ -Z unstable-options
 endif
 else
 ifeq ($(UNAME),Darwin)

src/test/run-make/issue-36710/foo.rs

@@ -1,8 +1,5 @@
 // Tests that linking to C++ code with global destructors works.
 
-// For linking libstdc++ on MinGW
-#![cfg_attr(all(windows, target_env = "gnu"), feature(native_link_modifiers))]
-
 extern "C" {
     fn get() -> u32;
 }