commit 28f9d86ea89f88b24f1d12c8e9d5ddc3f77da194
Author: Mark Wielaard <mark@klomp.org>
Date:   Fri May 6 00:29:28 2022 +0200

    debuginfod: Use MHD_USE_EPOLL for libmicrohttpd version 0.9.51 or higher
    
    Also disable MHD_USE_THREAD_PER_CONNECTION when using MHD_USE_EPOLL.
    
    https://sourceware.org/bugzilla/show_bug.cgi?id=29123
    
    Signed-off-by: Mark Wielaard <mark@klomp.org>

diff --git a/debuginfod/debuginfod.cxx b/debuginfod/debuginfod.cxx
index c02540f1..d4f47bf7 100644
--- a/debuginfod/debuginfod.cxx
+++ b/debuginfod/debuginfod.cxx
@@ -1,6 +1,6 @@
 /* Debuginfo-over-http server.
    Copyright (C) 2019-2021 Red Hat, Inc.
-   Copyright (C) 2021 Mark J. Wielaard <mark@klomp.org>
+   Copyright (C) 2021, 2022 Mark J. Wielaard <mark@klomp.org>
    This file is part of elfutils.
 
    This file is free software; you can redistribute it and/or modify
@@ -3899,7 +3899,14 @@ main (int argc, char *argv[])
         }
     }
 
-  unsigned int mhd_flags = ((connection_pool
+  /* Note that MHD_USE_EPOLL and MHD_USE_THREAD_PER_CONNECTION don't
+     work together.  */
+  unsigned int use_epoll = 0;
+#if MHD_VERSION >= 0x00095100
+  use_epoll = MHD_USE_EPOLL;
+#endif
+
+  unsigned int mhd_flags = ((connection_pool || use_epoll
 			     ? 0 : MHD_USE_THREAD_PER_CONNECTION)
 #if MHD_VERSION >= 0x00095300
 			    | MHD_USE_INTERNAL_POLLING_THREAD
@@ -3907,9 +3914,7 @@ main (int argc, char *argv[])
 			    | MHD_USE_SELECT_INTERNALLY
 #endif
 			    | MHD_USE_DUAL_STACK
-#ifdef MHD_USE_EPOLL
-			    | MHD_USE_EPOLL
-#endif
+			    | use_epoll
 #if MHD_VERSION >= 0x00095200
 			    | MHD_USE_ITC
 #endif