replaces prune_blog script with http/Makefile rules

http/bin/prune_blog

@@ -1,45 +0,0 @@
-#!/bin/sh -e
-
-BLOG="$1"
-BLOG_POST_PATTERN="${2:-*}"
-
-SRC="$(realpath src)"
-BLOGS="$(realpath blogs)"
-LAYOUTS="$(realpath share/layouts)"
-BLOG_DIR_IN_SRC="${SRC}/${BLOG}"
-BLOG_EXT=gmi
-
-for post in $(find "$BLOG_DIR_IN_SRC" -type f -and -name "$BLOG_POST_PATTERN")
-do
-  last_segment="${post##*\.}"
-  if [ "$last_segment" = "args" ]
-  then
-    continue
-  fi
-
-  post_rel_path="$(echo "$post" | cut -c${#BLOG_DIR_IN_SRC}- | cut -c3-)"
-  post_basename_len=$(( ${#post_rel_path} - ( ${#last_segment} + 1 ) ))
-  post_basename="$(echo "${post_rel_path}" | cut -c1-${post_basename_len})"
-	post_src="${BLOGS}/${BLOG}/${post_basename}.${BLOG_EXT}"
-	if [ -f "$post_src" ]
-	then
-    continue
-	fi
-
-  penultimate_segment_len=$(( ${#post} - ( ${#last_segment} + 1 ) ))
-  penultimate_segment="$(echo "${post}" | cut -c1-${penultimate_segment_len})"
-  penultimate_segment="${penultimate_segment##*\.}"
-  post_basename_len=$(( ${#post_rel_path} - ( ${#last_segment} + ${#penultimate_segment} + 2 ) ))
-  post_basename="$(echo "${post_rel_path}" | cut -c1-${post_basename_len})"
-  if [ -f "${LAYOUTS}/${penultimate_segment}.layout.${last_segment}" ]
-  then
-  	post_src="${BLOGS}/${BLOG}/${post_basename}.${BLOG_EXT}"
-   	if [ -f "$post_src" ]
-   	then
-        continue
-   	fi
-  fi
-
-  echo "No source file found to match post ${post} in blog ${BLOG}: removing ${post}"
-	rm -f "$post" "${post}.args"
-done