New comment by reback00 on void-packages repository

https://github.com/void-linux/void-packages/pull/31159#issuecomment-850332099

Comment:
I see. I just tried on my machine for updating my package for [akira](https://notabug.org/reback00/void-goodies/src/master/srcpkgs/akira). It worked so thought of committing the changes. Didn't know it has so many things attached to it.

Arch Linux has recently moved to goocanvas 3. I think I got some hints. Arch's `perl-goocanvas2` has had [these changes](https://github.com/archlinux/svntogit-community/commit/18f64b84269d2eab6ad8005b5997fe22e1d691e5#diff-3e341d2d9c67be01819b25b25d5e53ea3cdf3a38d28846cda85a195eb9b7203a) for updating to goocanvas 3. Mainly a sed line is needed. So we can have something like this:

```
pre_configure() {
	# For adapting to goocanvas 3.0
	sed -i "s/version => '2.0'/version => '3.0'/" lib/GooCanvas2.pm
}
```

[`gpredict`](https://aur.archlinux.org/packages/gpredict) and [`gpredict-git`](https://aur.archlinux.org/packages/gpredict-git/) haven't been updated for years, so we'd have to solve it ourselves. I've looked into `gpredict` source tree for `goocanvas` references and I found the most prominent instance in `configure`:

```
if pkg-config --atleast-version=2.0 goocanvas-2.0; then
    CFLAGS="$CFLAGS `pkg-config --cflags goocanvas-2.0`"
    LIBS="$LIBS `pkg-config --libs goocanvas-2.0`"
else
    as_fn_error $? "Gpredict requires libgoocanvas-2.0-dev" "$LINENO" 5
fi
...
GOOC_V=`pkg-config --modversion goocanvas-2.0`
```

`configure.ac` also has similar code. I used [this patch](https://gist.github.com/reback00/b3b0cf8d367d114900b0e2b00f1af37b) to update them. However, changing these to `3.0` shows this message:

```
WARNING: 'aclocal-1.15' is missing on your system.
         You should only need it if you modified 'acinclude.m4' or
         'configure.ac' or m4 files included by 'configure.ac'.
```

To remedy this, something like this has to be added to template:

```
pre_configure() {
	# To allow patched configure files by goocanvas 3 patches
	# Details: https://github.com/apereo/mod_auth_cas/issues/97
	touch *
}
```

I haven't looked into `gscan2pdf` ( cc @Hoshpak ) but I think it should build fine if `perl-goocanvas2` is updated.