The backtrace_symbols function expects a pointer to an array of void *
values, not a pointer to an array of a single element. Removing the
address operator ensures that the right type is used.

This avoids an unconditional failure of this probe with compilers that
treat incompatible pointer types as a compilation error.

Submitted upstream: <https://github.com/FreeRADIUS/freeradius-server/pull/5246>

diff --git a/configure b/configure
index ed01ee2bdd912f63..1e6d2284779cdd58 100755
--- a/configure
+++ b/configure
@@ -13390,7 +13390,7 @@ main (void)
 {
 
         void *sym[1];
-        backtrace_symbols(&sym, sizeof(sym))
+        backtrace_symbols(sym, sizeof(sym))
   ;
   return 0;
 }
diff --git a/configure.ac b/configure.ac
index 76320213b51d7bb4..6a689711d6c90483 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2168,7 +2168,7 @@ if test "x$ac_cv_header_execinfo_h" = "xyes"; then
         #include <execinfo.h>
       ]], [[
         void *sym[1];
-        backtrace_symbols(&sym, sizeof(sym)) ]])],[
+        backtrace_symbols(sym, sizeof(sym)) ]])],[
         AC_MSG_RESULT(yes)
         ac_cv_lib_execinfo_backtrace_symbols="yes"
       ],[