configure: Add libevent 2.0+ compatibility check for gpfdist

Add autoconf check for event_base_new function to ensure libevent 2.0
or later is available. This prevents build failures when older libevent
versions are installed that don't support the required API.

Author: yjhjstz

configure

@@ -14944,6 +14944,44 @@ else
   as_fn_error $? "libevent is required for gpfdist" "$LINENO" 5
 fi
 
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for event_base_new in libevent" >&5
+$as_echo_n "checking for event_base_new in libevent... " >&6; }
+if ${ac_cv_func_event_base_new+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <event.h>
+
+int
+main ()
+{
+struct event_base *base = event_base_new();
+if (base) event_base_free(base);
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+LIBS="-levent $ac_func_search_save_LIBS"
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_func_event_base_new=yes
+else
+  ac_cv_func_event_base_new=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_event_base_new" >&5
+$as_echo "$ac_cv_func_event_base_new" >&6; }
+if test "$ac_cv_func_event_base_new" = yes; then :
+  LIBS="-levent $LIBS"
+else
+  as_fn_error $? "libevent 2.0 or later is required for gpfdist (event_base_new function not found)" "$LINENO" 5
+fi
+
   EVENT_LIBS=" -levent"