Add intl/ICU support

src/SPC/builder/linux/LinuxBuilder.php

@@ -139,7 +139,7 @@ class LinuxBuilder extends BuilderBase
                 )
             );
         }
-        if ($this->getExt('swoole')) {
+        if ($this->getExt('swoole') || $this->getExt('intl')) {
             $extra_libs .= ' -lstdc++';
         }
         if ($this->getExt('imagick')) {

src/SPC/builder/linux/library/icu.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SPC\builder\linux\library;
+
+class icu extends LinuxLibraryBase
+{
+    public const NAME = 'icu';
+
+    protected function build()
+    {
+        $root = BUILD_ROOT_PATH;
+        shell()->cd($this->source_dir . '/source')
+            ->exec("{$this->builder->configure_env} ./runConfigureICU Linux --enable-static --disable-shared --prefix={$root}")
+            ->exec('make clean')
+            ->exec("make -j{$this->builder->concurrency}")
+            ->exec('make install');
+    }
+}