Merge pull request #479 in G/truffleruby from cleanup/find-exported-symbol to master

* commit '304bcca8b50c65c15eeb5fd5f32ed06907154fa1':
  Avoid using deprecated automatic LLVM function exports in backtraces test.

Author: eregon

test/truffle/cexts/backtraces/bin/backtraces

@@ -13,7 +13,7 @@ def puts_backtrace(backtrace)
 end
 
 puts "Test error in Ruby => C ext support => Ruby"
-RB_FUNCALLV = Truffle::Interop.import('@rb_funcallv')
+RB_FUNCALLV = Truffle::Interop.import('rb_funcallv')
 
 def callback
   raise 'Ruby callback error'
@@ -37,7 +37,7 @@ end
 puts
 puts "Test with an internal error from rb_mutex_lock()"
 LOCK = Mutex.new
-RB_MUTEX_LOCK = Truffle::Interop.import('@rb_mutex_lock')
+RB_MUTEX_LOCK = Truffle::Interop.import('rb_mutex_lock')
 
 LOCK.lock
 

test/truffle/cexts/backtraces/ext/backtraces/backtraces.c

@@ -49,4 +49,8 @@ void Init_backtraces() {
   rb_define_module_function(module, "foo", &foo, 1);
   rb_define_module_function(module, "qsort", call_qsort, 1);
   rb_define_module_function(module, "native_callback", native_callback, 1);
+
+  // used in the main script of the test
+  polyglot_export("rb_funcallv", &rb_funcallv);
+  polyglot_export("rb_mutex_lock", &rb_mutex_lock);
 }