Cast from pthread_t to pid_t via uintptr_t.

On 64bit NetBSD, pthread_t is a pointer and pid_t is an integer so
we cannot cast from pthread_t to pid_t directoly due to difference of
their size.


git-svn-id: https://google-glog.googlecode.com/svn/trunk@69 eb4d4688-79bd-11dd-afb4-1d65580434c0

src/utilities.cc

@@ -251,7 +251,7 @@ pid_t GetTID() {
   return GetCurrentThreadId();
 #else
   // If none of the techniques above worked, we use pthread_self().
-  return (pid_t)pthread_self();
+  return (pid_t)(uintptr_t)pthread_self();
 #endif
 }