run sanity checks on emcc -v even without inputs

emcc

@@ -528,6 +528,7 @@ There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR P
 
 elif len(sys.argv) == 2 and sys.argv[1] == '-v': # -v with no inputs
   print 'emcc (Emscripten GCC-like replacement + linker emulating GNU ld ) %s' % shared.EMSCRIPTEN_VERSION
+  shared.check_sanity(force=True)
   exit(subprocess.call([shared.CLANG, '-v']))
 
 def is_minus_s_for_emcc(newargs, i):

tests/test_sanity.py

@@ -319,7 +319,8 @@ fi
     output = self.check_working(EMCC)
     self.assertNotContained(SANITY_MESSAGE, output)
 
-    # also with -v
+    # also with -v, with or without inputs
+    output = self.check_working([EMCC, '-v'], SANITY_MESSAGE)
     output = self.check_working([EMCC, '-v', path_from_root('tests', 'hello_world.c')], SANITY_MESSAGE)
 
     # Make sure the test runner didn't do anything to the setup