Switch from using 'nacl_main' to 'main' entry point

ports/devenv/tests/devenv_small_test.cc

 // Copyright (c) 2014 The Native Client Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gtest/gtest.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <spawn.h>
 #include <unistd.h>
@@ skipping 436 matching lines @@
   EXPECT_EQ(0, close(p[0]));
   EXPECT_EQ(0, close(p[1]));
 
   int status;
   pid_t npid = waitpid(pid, &status, 0);
   EXPECT_EQ(pid, npid);
   EXPECT_TRUE(WIFEXITED(status));
   EXPECT_EQ(42, WEXITSTATUS(status));
 }
 
-extern "C" int nacl_main(int argc, char **argv) {
+int main(int argc, char **argv) {
   if (argc == 4 && strcmp(argv[1], "return") == 0) {
     return return_child(argc, argv);
   } else if (argc == 4 && strcmp(argv[1], "_exit") == 0) {
     return exit_child(argc, argv);
   } else if (argc == 2 && strcmp(argv[1], "pipes") == 0) {
     return pipes_child(argc, argv);
   } else if (argc == 4 && strcmp(argv[1], "cloexec_check") == 0) {
     return cloexec_check_child(argc, argv);
   } else if (argc == 2 && strcmp(argv[1], "echo") == 0) {
     char msg[] = "test";
     write(1, msg, sizeof(msg));
     return 0;
   }
   // Preserve argv[0] for use in some tests.
   argv0 = argv[0];
   testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }