MacOS build needs help2man

configure fails with the following

configure: error: missing required tool: help2man

README.md

@@ -58,7 +58,7 @@ $ sudo apt-get install libtool-bin
 ## MacOS:
 ```bash
 $ brew tap homebrew/dupes
-$ brew install binutils coreutils automake wget gawk libtool gperf gnu-sed --with-default-names grep
+$ brew install binutils coreutils automake wget gawk libtool help2man gperf gnu-sed --with-default-names grep
 $ export PATH="/usr/local/opt/gnu-sed/libexec/gnubin:$PATH"
 ```