Adapted from gdk-pixbuf, see the original at:
https://gitlab.gnome.org/GNOME/gdk-pixbuf/-/blob/master/gdk-pixbuf/io-xpm.c
rgb.txt is from X.org, see:
https://gitlab.freedesktop.org/xorg/app/rgb/-/blob/master/rgb.txt
Differences from the gdk-pixbuf version:
- GdkPixbuf replaced with struct lab_data_buffer
- Progressive and in-memory loading code removed
- Two functions that had separate BSD copyright rewritten
- Stores colors as ARGB32 earlier in the decoding process for efficiency
- Limited to 1024x1024 px and 1024 colors to prevent abuse
- Uses struct buf to build strings, in place of manual g_new/g_realloc
- Uses xzalloc/xznew_n for other memory allocations
- Uses g_strlcpy in place of banned strcpy/strncpy/strncat
- Uses standard C types (int, bool, etc.) in place of the GLib ones
- Follows labwc coding style (whitespace, braces, letter case, etc.)
- Et cetera ...
v2: add Perl fixes from @domo141
The default `titleLayout` is updated to `icon:iconify,max,close` which
replaces the window menu button with the window icon.
When the icon file is not found or could not be loaded, the window menu
icon as before is shown.
The icon theme can be selected with `<theme><icon>`.
This commit adds libsfdo as an optional dependency. `-Dicon=disabled` can
be passsed to `meson setup` command in order to disable window icon, in
which case the window icon is always replaced with a window menu button.
