[gtkmm-documentation] Refer to README files for building with Meson

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 69a0b50340659e4bfa0edcf1a3425f994c633a03
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Mon Dec 14 10:40:04 2020 +0100

    Refer to README files for building with Meson
    
    and suggest filing GitLab issues and merge requests.

 docs/tutorial/C/index-in.docbook | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)
---
diff --git a/docs/tutorial/C/index-in.docbook b/docs/tutorial/C/index-in.docbook
index c4de35f..d297e35 100644
--- a/docs/tutorial/C/index-in.docbook
+++ b/docs/tutorial/C/index-in.docbook
@@ -238,18 +238,14 @@ surprised, for instance, to find &gtkmm; 4.8 supplied by Debian's
 If your distribution does not provide a pre-built &gtkmm; package, or if you
 want to install a different version than the one provided by your distribution,
 you can also install &gtkmm; from source. The source code for &gtkmm; can
-be downloaded from <ulink url="http://www.gtkmm.org/";></ulink>.
+be downloaded from <ulink url="https://download.gnome.org/sources/gtkmm/";></ulink>.
 </para>
 <para>
   After you've installed all of the dependencies, download the &gtkmm; source
   code, unpack it, and change to the newly created directory. &gtkmm; can be
-  built and installed with the following sequence of commands:
+  built with Meson. See the <filename>README</filename> file in the &gtkmm; version
+  you've downloaded.
 </para>
-<screen>
-# ./configure
-# make
-# make install
-</screen>
 <note>
 <para>
   Remember that on a Unix or Linux operating system, you will probably need to
@@ -259,12 +255,12 @@ be downloaded from <ulink url="http://www.gtkmm.org/";></ulink>.
 </para>
 </note>
 <para>
-    The <filename>configure</filename> script will check to make sure all of
-    the required dependencies are already installed. If you are missing any
-    dependencies, it will exit and display an error.
+    The <filename>configure</filename> script or <command>meson</command> will check
+    to make sure all of the required dependencies are already installed. If you are
+    missing any dependencies, it will exit and display an error.
 </para>
 <para>
-    By default, &gtkmm; will be installed under the
+    By default, &gtkmm; if built with Autotools, will be installed under the
     <filename>/usr/local</filename> directory. On some systems you may need to
     install to a different location. For instance, on Red Hat Linux systems
     you might use the <literal>--prefix</literal> option with configure, like
@@ -7927,15 +7923,16 @@ any aspect of &gtkmm; that does not already have documentation, please
 consider contributing to this document.
 </para>
 <para>
-Ideally, we would like you to <ulink url="http://www.gtkmm.org/en/bugs.shtml";>provide a patch</ulink> to the
-<filename>docs/tutorial/C/index-in.docbook</filename> file. This file is currently
-in the <literal>gtkmm-documentation</literal> module in GNOME git.
+Ideally, we would like you to <ulink 
url="https://gitlab.gnome.org/GNOME/gtkmm-documentation/-/merge_requests";>
+provide a merge request</ulink> to the <filename>docs/tutorial/C/index-in.docbook</filename> file.
+This file is in the <literal>gtkmm-documentation</literal> module in GNOME git.
 </para>
 
 <para>
 If you do decide to contribute, please post your contribution to the
-&gtkmm; mailing list at <ulink url="mailto:gtkmm-list gnome org">&#60;gtkmm-list gnome org&#62;</ulink>. 
Also, be aware that
-the entirety of this document is free, and any addition you provide
+&gtkmm; mailing list at <ulink url="mailto:gtkmm-list gnome org">&#60;gtkmm-list gnome org&#62;</ulink>
+or as an issue or merge request to <ulink 
url="https://gitlab.gnome.org/GNOME/gtkmm-documentation";>GitLab</ulink>.
+Also, be aware that the entirety of this document is free, and any addition you provide
 must also be free. That is, people must be able to use any portion of
 your examples in their programs, and copies of this document
 (including your contribution) may be distributed freely.