[gtk+] make-pot: Document variables

[Matthias Clasen <matthiasc src gnome org>]

commit 76c66ef2ed0cfe62d40b6bf02520281debee17a5
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Mar 3 15:00:06 2015 -0500

    make-pot: Document variables
    
    Damn-lies will have to use one of these to override the name
    of the generated file. Lets document them all, while I still
    remember this.

 make-pot |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/make-pot b/make-pot
index 279cfaa..1abb590 100755
--- a/make-pot
+++ b/make-pot
@@ -14,6 +14,17 @@
 #   ./make-pot properties
 #
 # to generate po-properties/gtk30-properties.pot.
+#
+# Various things can be passed in by environment variables, which
+# are heavily inspired by the variables used in po/Makefile.in.in:
+#
+# XGETTEXT - path of the xgettext binary
+# top_srcdir - the location of the GTK+ checkout
+# srcdir - the directory where POTFILES.in is located (defaults to
+#          $top_srcdir/po or $top_srcdir/po-properties)
+# GETTEXT_PACKAGE - the gettext domain, used for naming the resulting
+#          .pot file (defaults to gtk30 or gtk30-properties)
+# XGETTEXT_KEYWORDS - --keyword arguments to pass to xgettext
 
 
 XGETTEXT="${XGETTEXT:-xgettext}"