diff -Naur a/configure.ac b/configure.ac
--- a/configure.ac	2019-02-02 18:00:40.000000000 +0100
+++ b/configure.ac	2025-01-13 12:13:48.087653985 +0100
@@ -233,6 +233,9 @@
     AC_DEFINE(HAVE_LIBLDAP, 1, [Define if LDAP support should be compiled])
     AC_RUN_IFELSE([AC_LANG_SOURCE([[
         #include <ldap.h>
+        #ifdef HAVE_STDLIB_H
+            #include <stdlib.h>
+        #endif
         int main()
         {
            LDAP *p;
@@ -342,6 +345,9 @@
 LIBS="$LIBS -ldb"
 AC_RUN_IFELSE([AC_LANG_SOURCE([[
     #include <db.h>
+    #ifdef HAVE_STDLIB_H
+        #include <stdlib.h>
+    #endif
     int main() 
     {
         int major, minor, patch;
@@ -377,6 +383,9 @@
 
 AC_RUN_IFELSE([AC_LANG_SOURCE([[
     #include <db.h>
+    #ifdef HAVE_STDLIB_H
+        #include <stdlib.h>
+    #endif
     int main() 
     {
         int major, minor, patch;
@@ -413,6 +422,9 @@
 
 AC_RUN_IFELSE([AC_LANG_SOURCE([[
     #include <db.h>
+    #ifdef HAVE_STDLIB_H
+        #include <stdlib.h>
+    #endif
     int main() 
     {
         int major, minor, patch;
@@ -441,6 +453,9 @@
 
 AC_RUN_IFELSE([AC_LANG_SOURCE([[
     #include <db.h>
+    #ifdef HAVE_STDLIB_H
+        #include <stdlib.h>
+    #endif
     int main() 
     {
         int major, minor, patch;
