Attempt to fix crashes with threads in GTK builds

* src/xgselect.c (xg_select): Call pselect via thread_select, not
directly, to avoid running Lisp (via unblock_input) when more than
one thread could be running.  (Bug#25247)
* src/process.c (wait_reading_process_output) [HAVE_GLIB]: Call
xg_select directly instead of through thread_select.
* src/xgselect.h (xg_select): Last 2 arguments are no longer
'const', for consistency with thread_select.

1 files changed, 10 insertions, 5 deletions

diff --git a/src/process.c b/src/process.c
index c5a46f992d7..c0c52c232b9 100644
--- a/src/process.c
+++ b/src/process.c
@@ -5341,18 +5341,23 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
             }
 #endif
 
+/* HAVE_GLIB builds call thread_select in xgselect.c.  */
+#ifdef HAVE_GLIB
+          nfds = xg_select (max_desc + 1,
+                            &Available, (check_write ? &Writeok : 0),
+                            NULL, &timeout, NULL);
+#else  /* !HAVE_GLIB */
           nfds = thread_select (
-#if defined (HAVE_NS)
+# ifdef HAVE_NS
                                 ns_select
-#elif defined (HAVE_GLIB)
-                                xg_select
-#else
+# else
                                 pselect
-#endif
+# endif
                                 , max_desc + 1,
                                 &Available,
                                 (check_write ? &Writeok : 0),
                                 NULL, &timeout, NULL);
+#endif  /* !HAVE_GLIB */
 
 #ifdef HAVE_GNUTLS
           /* GnuTLS buffers data internally.  In lowat mode it leaves