From 6de781b7d54ff902c0790fdb2b6b7fbd30de79cd Mon Sep 17 00:00:00 2001
From: dyx <dyx@dyx.name>
Date: Fri, 13 May 2022 02:07:35 +0800
Subject: [PATCH] update readme

---
 README.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/README.md b/README.md
index dc3c27a..275d9d8 100644
--- a/README.md
+++ b/README.md
@@ -33,6 +33,15 @@ execute the following commands in the source tree:
 
 It installs `shsub` to `/usr/local` by default.
 
+Building *shsub* requires:
+
+- `cc`(1): any C compiler which is compatible with *clang* or *gcc*
+
+- `m4`(1): the m4 macro processor
+
+They are all shipped with most Unix variants
+or can be installed from the package manager.
+
 USAGE
 -----