dln.c: check incompatible libruby

* dln.c (dln_load): check if a different libruby is loaded by the
  extension library, and then bail out to get rid of very frequent
  reported stale bug reports.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50412 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Fri May  1 13:30:24 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* dln.c (dln_load): check if a different libruby is loaded by the
+	  extension library, and then bail out to get rid of very frequent
+	  reported stale bug reports.
+
 Thu Apr 30 19:51:11 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* compile.c (iseq_compile_each): revert r46873 and r46875, not to

dln.c

@@ -1324,6 +1324,21 @@ dln_load(const char *file)
 	    error = dln_strerror();
 	    goto failed;
 	}
+# if defined RUBY_EXPORT
+	{
+	    static const char incompatible[] = "incompatible library version";
+	    void *ex = dlsym(handle, EXPORT_PREFIX"ruby_xmalloc");
+	    if (ex && ex != ruby_xmalloc) {
+
+#   if !defined __APPLE__
+		/* dlclose() segfaults */
+		dlclose(handle);
+#   endif
+		error = incompatible;
+		goto failed;
+	    }
+	}
+# endif
 
 	init_fct = (void(*)())(VALUE)dlsym(handle, buf);
 	if (init_fct == NULL) {