diff --git a/scripts/__init_script__.php b/scripts/__init_script__.php
index d13cfa6..da569d5 100644
--- a/scripts/__init_script__.php
+++ b/scripts/__init_script__.php
@@ -1,98 +1,102 @@
 <?php
 
 if (function_exists('pcntl_async_signals')) {
   pcntl_async_signals(true);
 } else {
   declare(ticks = 1);
 }
 
 function __phutil_init_script__() {
   // Adjust the runtime language configuration to be reasonable and inline with
   // expectations. We do this first, then load libraries.
 
   // There may be some kind of auto-prepend script configured which starts an
   // output buffer. Discard any such output buffers so messages can be sent to
   // stdout (if a user wants to capture output from a script, there are a large
   // number of ways they can accomplish it legitimately; historically, we ran
   // into this on only one install which had some bizarre configuration, but it
   // was difficult to diagnose because the symptom is "no messages of any
   // kind").
   while (ob_get_level() > 0) {
     ob_end_clean();
   }
 
   error_reporting(E_ALL | E_STRICT);
 
   $config_map = array(
     // Always display script errors. Without this, they may not appear, which is
     // unhelpful when users encounter a problem. On the web this is a security
     // concern because you don't want to expose errors to clients, but in a
     // script context we always want to show errors.
     'display_errors'              => true,
 
     // Send script error messages to the server's `error_log` setting.
     'log_errors'                  => true,
 
     // Set the error log to the default, so errors go to stderr. Without this
     // errors may end up in some log, and users may not know where the log is
     // or check it.
     'error_log'                   => null,
 
     // XDebug raises a fatal error if the call stack gets too deep, but the
     // default setting is 100, which we may exceed legitimately with module
     // includes (and in other cases, like recursive filesystem operations
     // applied to 100+ levels of directory nesting). Stop it from triggering:
     // we explicitly limit recursive algorithms which should be limited.
     //
     // After Feb 2014, XDebug interprets a value of 0 to mean "do not allow any
     // function calls". Previously, 0 effectively disabled this check. For
     // context, see T5027.
     'xdebug.max_nesting_level'    => PHP_INT_MAX,
 
     // Don't limit memory, doing so just generally just prevents us from
     // processing large inputs without many tangible benefits.
     'memory_limit'                => -1,
+
+    // See T13296. On macOS under PHP 7.3.x, PCRE currently segfaults after
+    // "fork()" if "pcre.jit" is enabled.
+    'pcre.jit' => 0,
   );
 
   foreach ($config_map as $config_key => $config_value) {
     ini_set($config_key, $config_value);
   }
 
   if (!ini_get('date.timezone')) {
     // If the timezone isn't set, PHP issues a warning whenever you try to parse
     // a date (like those from Git or Mercurial logs), even if the date contains
     // timezone information (like "PST" or "-0700") which makes the
     // environmental timezone setting is completely irrelevant. We never rely on
     // the system timezone setting in any capacity, so prevent PHP from flipping
     // out by setting it to a safe default (UTC) if it isn't set to some other
     // value.
     date_default_timezone_set('UTC');
   }
 
   // Adjust `include_path`.
   ini_set('include_path', implode(PATH_SEPARATOR, array(
     dirname(dirname(__FILE__)).'/externals/includes',
     ini_get('include_path'),
   )));
 
   // Disable the insanely dangerous XML entity loader by default.
   if (function_exists('libxml_disable_entity_loader')) {
     libxml_disable_entity_loader(true);
   }
 
   // Now, load libphutil.
 
   $root = dirname(dirname(__FILE__));
   require_once $root.'/src/__phutil_library_init__.php';
 
   PhutilErrorHandler::initialize();
   $router = PhutilSignalRouter::initialize();
 
   $handler = new PhutilBacktraceSignalHandler();
   $router->installHandler('phutil.backtrace', $handler);
 
   $handler = new PhutilConsoleMetricsSignalHandler();
   $router->installHandler('phutil.winch', $handler);
 }
 
 __phutil_init_script__();