feat(compiler): 添加内置 mpdecimal 头文件目录支持

- 添加 mpdecimal C 库头文件路径到编译器包含路径
- 添加 mpdecimal++ C++ 库头文件路径到编译器包含路径
- 支持在 Linux/macOS 平台下自动配置 mpdecimal 依赖库路径

src/Php/CompilerBase.php

@@ -2742,6 +2742,9 @@ class CompilerBase extends \PhpAot\Core\Translator
             // Linux/macOS
             $phpPaths = $platform->buildPhpIncludePaths($this->getPhpDir());
             $includePaths = array_merge($includePaths, $phpPaths);
+            // 内置 mpdecimal 头文件目录
+            $includePaths[] = $this->getPhpxDir() . '/thirdparty/mpdecimal/libmpdec';
+            $includePaths[] = $this->getPhpxDir() . '/thirdparty/mpdecimal/libmpdec++';
         }
 
         return $includePaths;