Re: m4-common

[Ryan Lortie <desrt desrt ca>]

karaj,

On Fri, Feb 20, 2015, at 13:56, Philip Withnall wrote:
> That’s excellent. It potentially means we can remove the advice to add
> AX_REQUIRE_DEFINED([YELP_HELP_INIT]) (etc.), since that’s now redundant
> for tarball builds. For git builds, we could assume JHBuild will handle
> this? That pattern is still useful for non-JHBuild git builds though, so
> I’m on the fence.

fwiw, I think the checking is still useful.  jhbuild isn't the only
place where people ever try to build our modules from git, nor is it a
flawless system that is always fully in-sync with itself.

AX_REQUIRE_DEFINED, of course is very very simple:

AC_DEFUN([AX_REQUIRE_DEFINED], [dnl
  m4_ifndef([$1], [m4_fatal([macro ]$1[ is not defined; is a m4 file
  missing?])])
])dnl AX_REQUIRE_DEFINED

so we could just write things like:

m4_ifndef([GLIB_GSETTINGS] [m4_fatal([gsettings automake support is
missing])])
m4_ifndef([PKG_CHECK_MODULES] [m4_fatal([pkg-config automake support is
missing])])
m4_ifndef([GTK_DOC_CHECK] [m4_fatal([gtk-doc automake support is
missing])])


Another idea is that we could expand AX_REQUIRE_DEFINED to take multiple
macro names, and then write this:

m4_ifndef([AX_REQUIRE_DEFINED] [m4_fatal([Required m4 macros are
missing])])
AX_REQUIRE_DEFINED([AX_COMPILER_FLAGS GLIB_SETTINGS PKG_CHECK_MODULES
GTK_DOC_CHECK])

which, at only two lines, manages to be completely foolproof against
missing macros (of any kind).

> > > I guess m4-common should also include a README which documents this,
> > > plus the reason for m4-common existing as a way to centralise
> > > downloading of the autoconf-archive macros we use.
> >
> > OK.  Will do that.
> >
> > > Would it also be worthwhile adding a dist-hook which causes dist to fail
> > > for m4-common, to make this really obvious?
> >
> > Sure.  I can do that too.
>
> Super, looking forward to it.

Both of these are done and the result is sitting in:

  https://github.com/desrt/m4-common

I think we're probably just about ready to put this in git.gnome.org and
add it to jhbuild.

Does anyone have any objections to that?

Cheers