add pillow dependencies (#258)

Co-authored-by: hay-kot <hay-kot@pm.me>

depends/download-and-extract.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+# Usage: ./download-and-extract.sh something https://example.com/something.tar.gz
+
+archive=$1
+url=$2
+
+if [ ! -f $archive.tar.gz ]; then
+    wget -O $archive.tar.gz $url
+fi
+
+rm -r $archive
+tar -xvzf $archive.tar.gz

depends/install_webp.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+# install webp
+
+archive=libwebp-1.2.0
+
+./download-and-extract.sh $archive https://raw.githubusercontent.com/python-pillow/pillow-depends/master/$archive.tar.gz
+
+pushd $archive
+
+./configure --prefix=/usr --enable-libwebpmux --enable-libwebpdemux && make -j4 && sudo make -j4 install
+
+popd