qemu: replace a gtk wrapper with directly setting environment from runqemu

qemu: replace a gtk wrapper with directly setting environment from runqemu

The wrapper is executed by host bash, and host bash refuses to run
when pseudo libc is preloaded via LD_PRELOAD (which is the case
when gl is enabled).

Only the fontconfig setting is carried over as local testing showed that
only that is necessary for the gui to look ok nowadays; adjust further
if necessary.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>