Linux: fix compatibility with libwebp-0.3 for use_system_libwebp=1 case.

tools/compile_test/compile_test.py

Index: tools/compile_test/compile_test.py
diff --git a/tools/compile_test/compile_test.py b/tools/compile_test/compile_test.py
index a52c0720209142af858d656a071ca43328dd3b16..79371a1fd05d2e03e098340527fc897faadad54c 100755
--- a/tools/compile_test/compile_test.py
+++ b/tools/compile_test/compile_test.py
@@ -21,6 +21,7 @@ import tempfile
 def DoMain(argv):
   parser = optparse.OptionParser()
   parser.add_option('--code')
+  parser.add_option('--run-linker', action='store_true')
   parser.add_option('--on-success', default='')
   parser.add_option('--on-failure', default='')
 
@@ -39,7 +40,12 @@ def DoMain(argv):
 
     o_path = os.path.join(tmpdir, 'test.o')
 
-    cxx_popen = subprocess.Popen([cxx, cxx_path, '-o', o_path, '-c'],
+    cxx_cmdline = [cxx, cxx_path, '-o', o_path]
+    if not options.run_linker:
+      cxx_cmdline.append('-c')
+    # Pass remaining arguments to the compiler.
+    cxx_cmdline += args
+    cxx_popen = subprocess.Popen(cxx_cmdline,
                                  stdout=subprocess.PIPE,
                                  stderr=subprocess.PIPE)
     cxx_stdout, cxx_stderr = cxx_popen.communicate()