Fix test breaking for MSVC

test/test_suite/statements/foreach_zstring.c3

@@ -3,7 +3,7 @@ import std;
 
 fn void main(String[] args)
 {
-    ZString* environ_arr = std::os::posix::environ;
+    ZString* environ_arr = null;
     foreach (idx, ZString &envvar : environ_arr) // #error: It's not possible to enumerate an expression of type 'ZString*'
     {}
 }