Fix compile_test.py for CXX values that contain spaces.

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 79371a1fd05d2e03e098340527fc897faadad54c..bbda4abfe54f327aabede26f400bebd5e1376d82 100755
--- a/tools/compile_test/compile_test.py
+++ b/tools/compile_test/compile_test.py
@@ -30,7 +30,9 @@ def DoMain(argv):
   if not options.code:
     parser.error('Missing required --code switch.')
 
-  cxx = os.environ.get('CXX', 'g++')
+  # The environment variable might expand to a string with spaces,
+  # e.g. "ccache g++". Convert it to a list suitable for argv.
+  cxx = os.environ.get('CXX', 'g++').split()
 
   tmpdir = tempfile.mkdtemp()
   try:
@@ -40,7 +42,7 @@ def DoMain(argv):
 
     o_path = os.path.join(tmpdir, 'test.o')
 
-    cxx_cmdline = [cxx, cxx_path, '-o', o_path]
+    cxx_cmdline = cxx + [cxx_path, '-o', o_path]
     if not options.run_linker:
       cxx_cmdline.append('-c')
     # Pass remaining arguments to the compiler.