add imagemagick (imagick) for macos, pkg-config for unix.=

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

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SPC\builder\linux\library;
+
+/**
+ * gmp is a template library class for unix
+ */
+class pkgconfig extends LinuxLibraryBase
+{
+    use \SPC\builder\unix\library\pkgconfig;
+
+    public const NAME = 'pkg-config';
+}