Update install script to install to custom location

install.sh

@@ -1,8 +1,29 @@
 #!/usr/bin/env bash
 
-python3 setup.py install --optimize=1
-cp nwg-panel.svg /usr/share/pixmaps/
-cp nwg-shell.svg /usr/share/pixmaps/
-cp nwg-processes.svg /usr/share/pixmaps/
-cp nwg-panel-config.desktop /usr/share/applications/
-cp nwg-processes.desktop /usr/share/applications/
+prefix=
+opts=()
+
+while true; do
+  case "$1" in
+    --prefix=*)
+      opts+=("$1")
+      eval "prefix=${1##--prefix=}"
+      shift
+      ;;
+    *)
+      break
+      ;;
+  esac
+done
+
+opts+=("$@")
+
+: ${prefix:="/usr"}
+
+python3 setup.py install --optimize=1 "${opts[@]}"
+mkdir -p $prefix/share/pixmaps/ $prefix/share/applications/
+cp nwg-panel.svg $prefix/share/pixmaps/
+cp nwg-shell.svg $prefix/share/pixmaps/
+cp nwg-processes.svg $prefix/share/pixmaps/
+cp nwg-panel-config.desktop $prefix/share/applications/
+cp nwg-processes.desktop $prefix/share/applications/