--- a/configure	2018-08-28 19:33:39.000000000 -0400
+++ b/configure	2023-09-05 19:44:27.311279263 -0400
@@ -6874,6 +6874,7 @@
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 #include <ctype.h>
+#include <stdlib.h>
 #if ((' ' & 0x0FF) == 0x020)
 # define ISLOWER(c) ('a' <= (c) && (c) <= 'z')
 # define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
@@ -7731,6 +7732,7 @@
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 #include <ctype.h>
+#include <stdlib.h>
 #if ((' ' & 0x0FF) == 0x020)
 # define ISLOWER(c) ('a' <= (c) && (c) <= 'z')
 # define TOUPPER(c) (ISLOWER(c) ? 'A' + ((c) - 'a') : (c))
@@ -10311,8 +10313,13 @@
   if test "$cross_compiling" = yes; then
   ac_cv_func_fork_works=cross
 else
-  cat >conftest.$ac_ext <<_ACEOF
+   cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+   cat confdefs.h >>conftest.$ac_ext
+   cat >>conftest.$ac_ext <<_ACEOF
 /* By Ruediger Kuhlmann. */
+      #include <stdlib.h>
       #include <sys/types.h>
       #if HAVE_UNISTD_H
       # include <unistd.h>