diff --git a/projects/knot-dns/Dockerfile b/projects/knot-dns/Dockerfile
index 9084bfcb2..22b103968 100644
--- a/projects/knot-dns/Dockerfile
+++ b/projects/knot-dns/Dockerfile
@@ -16,14 +16,26 @@
 
 FROM gcr.io/oss-fuzz-base/base-builder
 MAINTAINER jonathan.foote@gmail.com
-RUN apt-get update && \
-    apt-get install -y autoconf autogen automake autopoint bison flex gettext \
-                       gperf libtool make pkg-config texinfo wget
+RUN apt-get update && apt-get install -y \
+ autoconf \
+ autogen \
+ automake \
+ autopoint \
+ bison \
+ gettext \
+ gperf \
+ libtool \
+ make \
+ pkg-config \
+ texinfo \
+ wget
 
+ENV GNULIB_TOOL $SRC/gnulib/gnulib-tool
+RUN git clone git://git.savannah.gnu.org/gnulib.git
 RUN git clone --depth=1 --recursive https://git.savannah.gnu.org/git/libunistring.git
 RUN git clone --depth=1 https://git.lysator.liu.se/nettle/nettle.git
 RUN git clone --depth=1 https://gitlab.com/gnutls/gnutls.git
-
 RUN git clone --depth=1 https://gitlab.labs.nic.cz/knot/knot-dns
+
 WORKDIR knot-dns
 COPY build.sh $SRC/
diff --git a/projects/knot-dns/build.sh b/projects/knot-dns/build.sh
index 653d89b41..05fe8366a 100755
--- a/projects/knot-dns/build.sh
+++ b/projects/knot-dns/build.sh
@@ -22,9 +22,9 @@
 export DEPS_PATH=$SRC/knot_deps
 export PKG_CONFIG_PATH=$DEPS_PATH/lib/pkgconfig
 export CPPFLAGS="-I$DEPS_PATH/include"
-export CXXFLAGS="$CPPFLAGS -std=c++11 $CXXFLAGS"
-export CFLAGS="$CPPFLAGS $CFLAGS"
 export LDFLAGS="-L$DEPS_PATH/lib"
+export GNULIB_SRCDIR=$SRC/gnulib
+export GNULIB_TOOL=$SRC/gnulib/gnulib-tool
 
 cd $SRC/libunistring
 ./autogen.sh