update for comments

Author: stdpain

src/signalhandler.cc

@@ -53,9 +53,11 @@
 #  include <sys/ucontext.h>
 #endif
 #ifdef HAVE_UNISTD_H
+#  include <unistd.h>
+#endif
+#if defined (HAVE_SYS_SYSCALL_H) && defined (HAVE_SYS_TYPES_H)
 #  include <sys/syscall.h>
 #  include <sys/types.h>
-#  include <unistd.h>
 #endif
 
 namespace google {
@@ -218,16 +220,15 @@ void DumpSignalInfo(int signal_number, siginfo_t* siginfo) {
   std::ostringstream oss;
   oss << std::showbase << std::hex << std::this_thread::get_id();
   formatter.AppendString(oss.str().c_str());
-
-  formatter.AppendString(") ");
-
-  // Only linux has the PID of the signal sender in si_pid.
-#  ifdef GLOG_OS_LINUX
+#if defined (GLOG_OS_LINUX) && defined (HAVE_SYS_SYSCALL_H) && defined (HAVE_SYS_TYPES_H)
   pid_t tid = syscall(SYS_gettid);
-  formatter.AppendString("(LWP ");
+  formatter.AppendString(" LWP ");
   formatter.AppendUint64(tid, 10);
+#  endif
   formatter.AppendString(") ");
 
+  // Only linux has the PID of the signal sender in si_pid.
+#  ifdef GLOG_OS_LINUX
   formatter.AppendString("from PID ");
   formatter.AppendUint64(static_cast<uint64>(siginfo->si_pid), 10);
   formatter.AppendString("; ");