Merge pull request #824 from beryllium/bug823

PECL-UUID does not define a version constant, use phpversion() instead

src/Composer/Repository/PlatformRepository.php

@@ -89,7 +89,7 @@ class PlatformRepository extends ArrayRepository
                     break;
 
                 case 'uuid':
-                    $prettyVersion = UUID_VERSION;
+                    $prettyVersion = phpversion('uuid');
                     break;
 
                 case 'xsl':