compose: Document how to get compose-parse input from libX11 source

Signed-off-by: Simon McVittie <smcv@debian.org>

diff --git a/gtk/compose/compose-parse.c b/gtk/compose/compose-parse.c
index a1ec09d00d0964575d262b5ccc66106f773b5041..385a34fb77b287def30c06d845f55acb606903ec 100644 (file)
--- a/gtk/compose/compose-parse.c
+++ b/gtk/compose/compose-parse.c
@@ -7,6 +7,7 @@
  * character data, and definitions for the builtin compose table of GTK.
  * Run it like this:
  *
+ *   cpp -DXCOMM='#' Compose.pre | sed -e 's/^ *#/#/' > Compose
  *   compose-parse Compose sequences-little-endian sequences-big-endian chars gtkcomposedata.h
  *
  * The GTK build expects the output files to be in the source tree, in