raise an error if no functions were left to process

emscripten.py

@@ -127,6 +127,9 @@ def emscript(infile, settings, outfile, libraries=[], compiler_engine=None,
   if DEBUG and len(meta) > 1024*1024: print >> sys.stderr, 'emscript warning: large amounts of metadata, will slow things down'
   if DEBUG: print >> sys.stderr, '  emscript: split took %s seconds' % (time.time() - t)
 
+  if len(funcs) == 0:
+    raise RuntimeError('No functions to process. Make sure you prevented LLVM from eliminating them as dead (use EXPORTED_FUNCTIONS if necessary, see the FAQ)')
+
   #if DEBUG:
   #  print >> sys.stderr, '========= pre ================\n'
   #  print >> sys.stderr, ''.join(pre)