Taking upstream at request of Gentoo devs.

According to the man page, startx is supposed to take the same command-line
syntax as xinit, and provide some extra services like setting up authorization
and such like.  However, xinit handles single-quoted command line args with
embedded spaces correctly, but startx does not.

The script assumes that each individual command-line parameter has no embedded
spaces, with constructs like:
     clientargs="$clientargs $1"
Thus, any special quoting or grouping on the startx command line won't get
propagated to xinit correctly.

I discovered this problem while trying to do some testing for another bug. 
Boiled down, this command works:
     xinit /bin/sh -vxc 'xsetroot -solid orange; sleep 5' -- :1
but this command, which per the docs should work, doesn't:
     startx /bin/sh -vxc 'xsetroot -solid orange; sleep 5' -- :1
The former starts the server, sets the background color and waits for 5 seconds,
like it should.  The latter starts the server and bails immediately since
xsetroot runs with no args and sleep isn't run at all.

I used a little sed command that I hope is adequate to quote for whatever shells
you intend to support as /bin/sh.  Will upload patch.