diff --git a/debian/patches/debian/0001-build.patch b/debian/patches/debian/0001-build.patch
index a40ae04..72b7986 100644
--- a/debian/patches/debian/0001-build.patch
+++ b/debian/patches/debian/0001-build.patch
@@ -4,7 +4,7 @@ Description: Avoid overwriting build-environment.
 diff -Naurp plzip.orig/configure plzip/configure
 --- plzip.orig/configure
 +++ plzip/configure
-@@ -21,9 +21,9 @@ datarootdir='$(prefix)/share'
+@@ -22,9 +22,9 @@ datarootdir='$(prefix)/share'
  infodir='$(datarootdir)/info'
  mandir='$(datarootdir)/man'
  CXX=g++
@@ -16,4 +16,4 @@ diff -Naurp plzip.orig/configure plzip/configure
 +#LDFLAGS=
  
  # checking whether we are using GNU C++.
- /bin/sh -c "${CXX} --version" > /dev/null 2>&1 ||
+ /bin/sh -c "${CXX} --version" > /dev/null 2>&1 || { CXX=c++ ; CXXFLAGS=-O2 ; }