Add comment, fix 5.3 build

src/Composer/DependencyResolver/PoolBuilder.php

@@ -113,6 +113,7 @@ class PoolBuilder
             $loadNames = $newLoadNames;
         }
 
+        // filter packages according to all the require statements collected for each package
         foreach ($this->packages as $i => $package) {
             // we check all alias related packages at once, so no need to check individual aliases
             // isset also checks non-null value

src/Composer/Util/MetadataMinifier.php

@@ -52,7 +52,7 @@ class MetadataMinifier
                 continue;
             }
 
-            $minifiedVersion = [];
+            $minifiedVersion = array();
 
             // add any changes from the previous version
             foreach ($version as $key => $val) {