Author: Daniel Baumann <mail@daniel-baumann.ch>
Description: Avoid overwriting build-environment.

diff -Naurp clzip.orig/configure clzip/configure
--- clzip.orig/configure	2013-07-19 17:24:58.332735484 +0200
+++ clzip/configure	2013-07-19 17:30:30.803563946 +0200
@@ -20,10 +20,10 @@ bindir='$(exec_prefix)/bin'
 datarootdir='$(prefix)/share'
 infodir='$(datarootdir)/info'
 mandir='$(datarootdir)/man'
-CC=gcc
-CPPFLAGS=
-CFLAGS='-Wall -W -O2'
-LDFLAGS=
+#CC=gcc
+#CPPFLAGS=
+#CFLAGS='-Wall -W -O2'
+#LDFLAGS=
 
 # checking whether we are using GNU C.
 ${CC} --version > /dev/null 2>&1