use <httpget> instead of wget for platform independence

build.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <project name="uw-php-security" default="main">
 
+    <property name="composer.version" value="1.1.3"/>
+
     <!-- Default build target -->
     <target name="main" description="Default build target">
         <phingcall target="composer-install" />
@@ -19,7 +21,9 @@
                 <available file="composer.phar"/>
             </not>
             <then>
-                <exec command="wget https://getcomposer.org/composer.phar" passthru="true"/>
+                <httpget dir="${project.basedir}"
+                         url="https://getcomposer.org/download/${composer.version}/composer.phar"
+                         followRedirects="true"/>
             </then>
         </if>
     </target>
@@ -36,8 +40,9 @@
                 <available file="phpunit.phar"/>
             </not>
             <then>
-                <exec command="wget https://phar.phpunit.de/phpunit.phar" passthru="true"
-                      checkreturn="true"/>
+                <httpget dir="${project.basedir}"
+                         url="https://phar.phpunit.de/phpunit.phar"
+                         followRedirects="true"/>
             </then>
         </if>
     </target>