remarks about building poke

[Bruno Haible]

Hi José,

Building poke is, so far, a bit challenging. Here are some suggestions
for improving it.

1) This patch to the HACKING file
     - makes it straightforward to pull the required jitter version from
       Luca Saiu's not-so-straightforward site,
     - mentions the flags to use for configuring poke after, not before
       the instructions for building jitter.

================================================================================
diff --git a/HACKING b/HACKING
index 5cc9d83..7b60616 100644
--- a/HACKING
+++ b/HACKING
@@ -133,19 +133,20 @@ Jitter
 ~~~~~~
 
 In order to build and run poke, you need Luca Saiu's jitter.  Jitter
-is available in http://ageinghacker.net/git/cgit.cgi/jitter.  The
-specific revision you need is
-745ba29c15dd56c60a7ab0320e09c1ca705018b7.
+is available in http://ageinghacker.net/git/cgit.cgi/jitter.  You need
+a specic revision. The command to download it is
+  wget 
http://ageinghacker.net/git/cgit.cgi/jitter/snapshot/jitter-745ba29c15dd56c60a7ab0320e09c1ca705018b7.tar.xz
 
-Configure and install jitter in some prefix.  When configuring poke,
-specify the location of the jitter installation with --with-jitter.
-
-For the time being, you should also use when configuring jitter::
+Configure and install jitter in some prefix.  For the time being, you
+should use when configuring jitter::
 
   --disable-dispatch-minimal-threading --disable-dispatch-no-threading
 
 or, alternatively, use ``--enable-debug`` when configuring poke.
 
+When configuring poke, specify the location of the jitter installation
+with --with-jitter.
+
 Building
 ~~~~~~~~
 
================================================================================

2) When libtextstyle is not installed, you get a link error. To fix this,
gnulib has added the missing functions in the dummy textstyle.in.h
https://lists.gnu.org/archive/html/bug-gnulib/2019-10/msg00041.html .
Additionally, since poke uses gnulib as a submodule, you need to upgrade
this submodule.

3) Makefile.am and configure.ac tell 'make' to recurse into the etc/
directory. But there is no etc/Makefile.am. I had to apply this workaround
to get over it:

    # Fix "configure.ac:104: error: required file 'etc/Makefile.in' not found" 
error.
    $ sed -i -e '/etc\/Makefile/d' poke/configure.ac
    $ sed -i -e 's/ etc / /g' poke/Makefile.am

Probably this etc/Makefile.am should install poke-default.css in public
locations?

4) Since I have the Boehm GC installed in a prefix different from the
one that contains pkg-config, I needed to set PKG_CONFIG_PATH so that
pkg-config finds it:
  export PKG_CONFIG_PATH=${INSTALL_PREFIX_OF_LIBGC}/lib/pkgconfig
This could be mentioned in the HACKING file.

5) You can add a pointer to the continuous integration into HACKING.
I would suggest a paragraph like this:

Continuous integration
~~~~~~~~~~~~~~~~~~~~~~

The package is built automatically, at regular intervals.  You find the
latest build results here:
  https://gitlab.com/gnu-poke/ci-distcheck/pipelines
  https://gitlab.com/gnu-poke/ci-distcheck/-/jobs?scope=finished


Bruno