diff -Nrup a/libcext/m4/eso.m4 b/libcext/m4/eso.m4
--- a/libcext/m4/eso.m4	2019-02-15 11:47:40.000000000 -0700
+++ b/libcext/m4/eso.m4	2019-12-19 05:35:50.805784105 -0700
@@ -558,7 +558,7 @@ AC_LANG_PROGRAM(
 #include <string.h>
 ]],
 [[
-    char s1[128], s2[128];
+    volatile char s1[128], s2[128];
 
     sprintf(s1, "%p", s1);
     sprintf(s2, "%#x", s1);
diff -Nrup a/libcext/configure b/libcext/configure
--- a/libcext/configure	2019-07-17 06:29:00.000000000 -0600
+++ b/libcext/configure	2019-12-19 05:36:38.808605520 -0700
@@ -15415,7 +15415,7 @@ int
 main ()
 {
 
-    char s1[128], s2[128];
+    volatile char s1[128], s2[128];
 
     sprintf(s1, "%p", s1);
     sprintf(s2, "%#x", s1);