Revert my two recent process.c changes

Revert "Improve last commit to process.c" and "Remove callback-handled
channels from Available set" because they did not fix bug#21313.

This reverts commits bfa1aa8e2bdaf14adbbf1e9e824051d3f740694c and
27f871907cc24f33a7d12ac3a4ab71a88f0bc554..

1 files changed, 6 insertions, 12 deletions

diff --git a/src/process.c b/src/process.c
index 42dd17c57e0..55f31a02673 100644
--- a/src/process.c
+++ b/src/process.c
@@ -5031,18 +5031,12 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
       for (channel = 0; channel <= max_input_desc; ++channel)
         {
           struct fd_callback_data *d = &fd_callback_info[channel];
-          if (d->func)
-            {
-              if (d->condition & FOR_READ
-                  && FD_ISSET (channel, &Available))
-                {
-                  d->func (channel, d->data);
-                  FD_CLR (channel, &Available);
-                }
-              else if (d->condition & FOR_WRITE
-                       && FD_ISSET (channel, &write_mask))
-                d->func (channel, d->data);
-            }
+          if (d->func
+              && ((d->condition & FOR_READ
+                   && FD_ISSET (channel, &Available))
+                  || (d->condition & FOR_WRITE
+                      && FD_ISSET (channel, &write_mask))))
+            d->func (channel, d->data);
         }
 
       for (channel = 0; channel <= max_process_desc; channel++)