--- configure.ac.old	2018-02-28 10:53:45.000000000 +0100
+++ configure.ac	2018-03-02 05:04:20.000000000 +0100
@@ -22,7 +22,7 @@ AC_PROG_LIBTOOL
 COMP_VERSION=nxcomp_version
 AC_SUBST([COMP_VERSION])
 
-LT_COMP_VERSION=[`echo $COMP_VERSION | sed -r -e 's/^([0-9]+\.[0-9]+\.[0-9]+).*$/\1/' -e 's/\./:/g'`]
+LT_COMP_VERSION=[`echo $COMP_VERSION | sed -E -e 's/^([0-9]+\.[0-9]+\.[0-9]+).*$/\1/' -e 's/\./:/g'`]
 AC_SUBST([LT_COMP_VERSION])
 
 # Silence warning: ar: 'u' modifier ignored since 'D' is the default