Fix a configure check that happens to trigger and implicit function
declaration error.

Fixed slightly differently in upstream via:

commit 516032ec39169d05c613de0e8ee10845658748ff
Author: Quentin Armitage <quentin@armitage.org.uk>
Date:   Sun Apr 17 18:02:18 2022 +0100

    config parser: Fix segfault caused by extra '}' and other parser fixes
    
    If there was a configuration error in a block, e.g. a vrrp_instance,
    keepalived would apply the configuration in the rest of the block to
    the previous object of that type, e.g. the previous vrrp instance. If
    there had been no previous instance, keepalived would probably segfault.
    
    This commit changes the way the parser works. A new instance of an
    object, e.g. a VRRP instance or a virtual server, is only added to the
    list of those objects once the configuration of that object is complete.
    In particular it no longer applies the configuration to the last entry
    on the list of the relevant object type, but keeps a point to the
    object currently being configured.
    
    Signed-off-by: Quentin Armitage <quentin@armitage.org.uk>

diff --git a/configure b/configure
index 7cd6c4f614930391..b099b8f42aca1cba 100755
--- a/configure
+++ b/configure
@@ -6382,7 +6382,7 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 
         #include <stdio.h>
 
-        static int func(int i) __attribute__((error("deliberate error")))
+        static int __attribute__((error("deliberate error"))) func(int i)
 	{
 	  return i * 2;
 	}
diff --git a/configure.ac b/configure.ac
index 350a9f4e9567518c..5546143b4630aff6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -792,7 +792,7 @@ AC_COMPILE_IFELSE(
       [[
         #include <stdio.h>
 
-        static int func(int i) __attribute__((error("deliberate error")))
+        static int __attribute__((error("deliberate error"))) func(int i)
 	{
 	  return i * 2;
 	}