We compile PHP with the "readline" sys lib instead of libedit

Both options seem to be acceptable, but we get readline out of the box on lambda, and there seems to be issues with libedit anyway (docker-library/php#1187)

Author: mnapoli

tests/test_2_extensions.php

@@ -61,7 +61,7 @@
     'openssl' => strlen(openssl_random_pseudo_bytes(1)) === 1,
     'pntcl' => function_exists('pcntl_fork'),
     'pcre' => preg_match('/abc/', 'abcde', $matches) && $matches[0] === 'abc',
-    'readline' => READLINE_LIB === 'libedit',
+    'readline' => READLINE_LIB === 'readline',
     'reflection' => class_exists(\ReflectionClass::class),
     'session' => session_status() === PHP_SESSION_NONE,
     'zip' => class_exists(\ZipArchive::class),