hash.c: GC guards

* hash.c (env_delete, env_aset): prevent environment variable
  names from GC while ruby_setenv.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51935 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

hash.c

@@ -2816,6 +2816,7 @@ env_delete(VALUE obj, VALUE name)
 
 	ruby_setenv(nam, 0);
 	if (ENVMATCH(nam, PATH_ENV)) {
+	    RB_GC_GUARD(name);
 	    path_tainted = 0;
 	}
 	return value;
@@ -3151,6 +3152,7 @@ env_aset(VALUE obj, VALUE nm, VALUE val)
 
     ruby_setenv(name, value);
     if (ENVMATCH(name, PATH_ENV)) {
+	RB_GC_GUARD(nm);
 	if (OBJ_TAINTED(val)) {
 	    /* already tainted, no check */
 	    path_tainted = 1;