fix apr_strnatcasecmp in apr before 1.6 compat

Author: icing

ChangeLog

@@ -1,6 +1,8 @@
  * Fix the ARI related `replaces` property in ACME order creation to only
    be used when the CA supports ARI and it is enabled in the menu config.
    Fixes #406.
+ * Fix compatibility with APR versions before 1.6.0 which do not have
+   `apr_cstr_casecmp` and should use `apr_strnatcasecmp` instead.
 
 v2.6.7
 ----------------------------------------------------------------------------------------------------

src/md_util.h

@@ -27,7 +27,7 @@
 #else
 /* Define a (poor) backwards-compatibility entry point for
  * apr_cstr_casecmp() from APR 1.6. */
-#define apr_cstr_casecmp apr_natcasecmp
+#define apr_cstr_casecmp apr_strnatcasecmp
 #endif
 
 struct apr_array_header_t;