Fail early if libtool is not present.

6c1be632 · Hisham · 642ccb49 · 6c1be632
Commit 6c1be632 authored May 19, 2016 by Hisham
--- a/configure.ac
+++ b/configure.ac
@@ -2,6 +2,7 @@
 # Process this file with autoconf to produce a configure script.

 AC_PREREQ(2.65)
+LT_PREREQ([2.4.2])
 AC_INIT([htop],[2.0.1],[hisham@gobolinux.org])

 SOURCE_DATE_EPOCH="${SOURCE_DATE_EPOCH:-$(date +%s)}"