[PATCH] glib needed only when enable_librsvg, gettext only when enable_librsvg or cross-compile

[Tor Lillqvist]

> But I don't know how to check for cross-compiling
> for 'gettext', or is it related at all?

I think it was so that gettext is needed by cross_toolset because
gettext is needed by glib and glib-genmarshal (as a *build* platform
binary) is needed when building glib (for the *host* platform). Hmm.
Does that make any sense, I wonder? Perhaps not... We probably should
drop gettext from cross_toolset/prj/build.lst and see what happens...

As we don't build any of the LGPL librsvg stack, glib and gettext for
iOS any more, and as Linux build hosts use a system glib and gettext,
probably the combination where it matters is cross-compilation for
Android on Mac OS X. I am not doing that combination myself any more,
somebody else will have to check...

--tml