Add cgi SAPI

Author: crazywhalecc

README-zh.md

@@ -207,6 +207,7 @@ bin/spc --version
 - `--build-micro`：构建 phpmicro 自执行二进制
 - `--build-fpm`：构建 fpm
 - `--build-embed`：构建 embed（libphp）
+- `--build-cgi`: 构建 cgi（不推荐）
 - `--build-all`：构建所有
 
 如果出现了任何错误，可以使用 `--debug` 参数来展示完整的输出日志，以供排查错误：

README.md

@@ -218,6 +218,7 @@ Now we support `cli`, `micro`, `fpm` and `embed` SAPI. You can use one or more o
 - `--build-micro`: build static phpmicro self-extracted executable
 - `--build-fpm`: build static fpm binary
 - `--build-embed`: build embed (libphp)
+- `--build-cgi`: build cgi binary (not recommended)
 - `--build-all`: build all
 
 If anything goes wrong, use `--debug` option to display full terminal output: