install-build-deps.sh: avoid overwriting liblz4.pc if provided by liblz4-dev

Signed-off-by: Tim Janik <[email protected]>

Author: tim-janik

install-build-deps.sh

@@ -24,7 +24,8 @@ if [ -e /usr/bin/apt-get ] ; then
   sudo apt-get -y install zsync git libarchive-dev autoconf libtool make gcc g++ libtool libfuse-dev \
   liblzma-dev libglib2.0-dev libssl-dev libinotifytools0-dev liblz4-dev libcairo-dev desktop-file-utils cmake
   # libtool-bin might be required in newer distributions but is not available in precise
-  sudo cp resources/liblz4.pc /usr/lib/$ARCH-linux-gnu/pkgconfig/
+  test -e /usr/lib/$ARCH-linux-gnu/pkgconfig/liblz4.pc ||
+    sudo cp -v resources/liblz4.pc /usr/lib/$ARCH-linux-gnu/pkgconfig/
   if cat /etc/lsb-release | grep 14.04 2>&1 >/dev/null; then
     export CMAKE_VERSION=3.10.0
     # sometimes, using a crowbar is easier than fiddling with PPAs