diff -Nrup a/configure b/configure

--- a/configure	2006-09-20 16:34:03.000000000 -0600

+++ b/configure	2019-12-19 06:07:54.302627575 -0700

@@ -11959,7 +11959,7 @@ cat >>conftest.$ac_ext <<_ACEOF

 /* end confdefs.h.  */

 #include <malloc.h>

-int test1() {

+__attribute__ ((used)) int test1() {

     return _alloca(42);

 }

diff -Nrup a/configure.ac b/configure.ac

--- a/configure.ac	2006-05-03 08:10:36.000000000 -0600

+++ b/configure.ac	2019-12-19 06:07:27.468727400 -0700

@@ -451,7 +451,7 @@ dnl Visual C++ doesn't have alloca, does

 AC_CACHE_CHECK(for _alloca, ac_cv_c__alloca,

 [AC_TRY_LINK([

 #include <malloc.h>

-int test1() {

+__attribute__ ((used)) int test1() {

     return _alloca(42);

 }

 ],