graphics/xpaint: Update to 3.1.2?

[Frederic Fauberteau <triaxx%NetBSD.org@localhost>]

I updated graphics/xpaint to 3.1.2 but the result is not really well. It builds and installs successfully and pkglint thinks it looks almost fine (it warns about my use of TOOLS_PLATFORM.gunzip).

Among the things that appear wrong to me:
  * Inelegant parts of the Makefile:
    o The substitution that fixes the link of the libXaw3dXft include directory to ${WRKSRC}/xaw_incdir. Actually, the Makefile links the include directory of libXaw3dXft to the source directory to virtually add a subdirectory in the preprocessor inclusions (#include "xaw_incdir/XXX.h"). Maybe we should patch it to do otherwise, but I don't really have an idea...
    o The uncompression of the XPM files. I am not sure that calling ${TOOLS_PLATFORM.gunzip} is the correct way to run gunzip...
  * The menu items do not appear while the submenu items do
  * The file browser seems to be broken
  * The focus on menu items seems to require a long press on the mouse button

I do not know if the issues come from xpaint or libXaw3dXft. I have no experience in X11 programming and debugging this program seems like a hard job for me. Therefore, I commit it on pkgsrc-wip. Is someone interested in taking a look on wip/xpaint to try to make it work perfectly? It would be great if you could have this tool working for old systems with few performance.