GNUmakefile: add a comment showing how to define $(PN) cleverly.

diff --git a/GNUmakefile b/GNUmakefile
index fba3b3799ec64f9199ca8204aa5f444a759591db..26bb59f2cb9e3aaa2d74be2fbeb3539cf572ae08 100644 (file)
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -6,6 +6,11 @@
 LATEX = pdflatex -file-line-error -halt-on-error
 
 # The name of this document.
+#
+# For example, to use the name of our parent directory:
+#
+# PN = $(notdir $(realpath .))
+#
 PN = examples
 
 # A space-separated list of bib files. These must all belong to paths