PPAPI/NaCl: Fix IPC proxy build; pthread_t changed

base/threading/platform_thread_posix.cc

Index: base/threading/platform_thread_posix.cc
diff --git a/base/threading/platform_thread_posix.cc b/base/threading/platform_thread_posix.cc
index 388f8baf62425ab50e6ecc7ab0583a78940daf89..77039a0add82c50f56fa3a3a0e385745d5138f39 100644
--- a/base/threading/platform_thread_posix.cc
+++ b/base/threading/platform_thread_posix.cc
@@ -160,8 +160,11 @@ PlatformThreadId PlatformThread::CurrentId() {
   return syscall(__NR_gettid);
 #elif defined(OS_ANDROID)
   return gettid();
-#elif defined(OS_NACL) || defined(OS_SOLARIS)
+#elif defined(OS_SOLARIS)
   return pthread_self();
+#elif defined(OS_NACL)
+  // Pointers are 32-bits in NaCl.

[Mark Seaborn, 2012/05/22 16:39:39]

You might also comment that we're assuming nacl-newlib's pthread implementation.
 NaCl itself does not specify that pthread_t is a pointer.

+  return reinterpret_cast<int32>(pthread_self());

[Mark Seaborn, 2012/05/22 16:39:39]

FYI, this would break again if nacl-newlib's libpthread changed the type back to
int, because an int->int reinterpret_cast is rejected by some compilers.  A
C-style cast would avoid that problem.

 #elif defined(OS_POSIX)
   return reinterpret_cast<int64>(pthread_self());
 #endif