diff -ru clzip-1.12.orig/configure clzip-1.12/configure--- clzip-1.12.orig/configure 2021-01-01 16:37:55.000000000 +0100+++ clzip-1.12/configure 2021-01-13 12:42:25.898898082 +0100@@ -22,7 +22,7 @@ mandir='$(datarootdir)/man' CC=gcc CPPFLAGS=-CFLAGS='-Wall -W -O2'+CFLAGS ?= '-Wall -W -O2' LDFLAGS= # checking whether we are using GNU C.