While some of the examples include a "board.ld" style file, some of them were
pointing to the libopencm3 provided chip specific ld scripts. When
TOOLCHAIN_DIR has been overridden, those paths were no longer valid/correct.
This is not specifically an L1 example, but it lives beside the L1 "usart"
example to show how easy it is to add semihosting support to existing code.
Tested with the by now relatively old g-a-e 2012q4 release and
OpenOcd 0.8.0-dev-00011-g70a2ffa (2013-05-14-19:41)
