Work properly without dl() function

Closes #14

bigmath.inc.php

@@ -198,7 +198,7 @@ abstract class BigMath {
       }
 
       // Try to load dynamic modules.
-      if (!$loaded) {
+      if (!$loaded && function_exists('dl')) {
         foreach ($ext['modules'] as $module) {
           if (@dl($module . "." . PHP_SHLIB_SUFFIX)) {
             $loaded = true;

test.php

@@ -74,7 +74,7 @@
  foreach ($extensions as $ext) {
   if ($ext['extension'] && extension_loaded($ext['extension'])) {
    $loaded = true;
-  } else {
+  } elseif (function_exists('dl')) {
    foreach ($ext['modules'] as $module) {
     if (@dl($module . "." . PHP_SHLIB_SUFFIX)) {
      $loaded = true;