Update readme (new tagline; more compat info)

diff --git a/README.markdown b/README.markdown
index 0941b52095f1609285389d7663537562abfa57d6..9d518896eaed97d4e8903bde4c9390a71c1deda3 100644 (file)
--- a/README.markdown
+++ b/README.markdown
@@ -1,6 +1,6 @@
 # ⛩️📰 书社
 
-<b>An X·S·L·T‐based static site generator.</b>
+<b>A make·file for X·M·L.</b>
 
 <dfn>⛩️📰 书社</dfn> aims to make it easy to generate websites with
   X·S·L·T and G·N·U Make.
@@ -18,6 +18,15 @@ It makes things easier by :⁠—
 
 It aims to do this with zero dependencies beyond the programs already
   installed on your computer.
+(On Linux machines, you may need to install `libxml2-utils` to get the
+  commandline programs from `libxml2`.)
+
+**Note:**
+⛩️📰 书社 requires functionality present in G·N·U Make 3.81 (or later)
+  and will not work in previous versions, or other implementations of
+  Make.
+Compatibility with later versions of G·N·U Make is assumed, but not
+  tested.
 
 ## Nomenclature
 
@@ -462,4 +471,4 @@ Source files are licensed under the terms of the <cite>Mozilla Public
   License, version 2.0</cite>.
 For more information, see [LICENSE](./LICENSE).
 
-[draft-phillips-record-jar-01]: <https://datatracker.ietf.org/doc/html/draft-phillips-record-jar-01>
\ No newline at end of file
+[draft-phillips-record-jar-01]: <https://datatracker.ietf.org/doc/html/draft-phillips-record-jar-01>