Make all of stdout/stderr/stdin pipes close-on-exec when spawing child processes.

runtime/bin/process_macos.cc

Index: runtime/bin/process_macos.cc
diff --git a/runtime/bin/process_macos.cc b/runtime/bin/process_macos.cc
index d24a5994ecfdb57ee1ded112f7ee564ea190f252..4ba17a94fd16b4aeb4c60944d1d835bd83da8611 100644
--- a/runtime/bin/process_macos.cc
+++ b/runtime/bin/process_macos.cc
@@ -392,6 +392,7 @@ class ProcessStarter {
       return CleanupAndReturnError();
     }
     FDUtils::SetCloseOnExec(read_in_[0]);
+    FDUtils::SetCloseOnExec(read_in_[1]);
 
     // For detached processes the pipe to connect stderr and stdin are not used.
     if (mode_ != kDetached) {
@@ -400,11 +401,13 @@ class ProcessStarter {
         return CleanupAndReturnError();
       }
       FDUtils::SetCloseOnExec(read_err_[0]);
+      FDUtils::SetCloseOnExec(read_err_[1]);
 
       result = TEMP_FAILURE_RETRY(pipe(write_out_));
       if (result < 0) {
         return CleanupAndReturnError();
       }
+      FDUtils::SetCloseOnExec(write_out_[0]);
       FDUtils::SetCloseOnExec(write_out_[1]);
     }