Bash seems to be smart enough to source the file when execve returns
ENOEXEC, but other shells might not be.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
names (gsed/gnused), checking for a basic OS X sed feature in command
line option handling, checking the actual result of the sed run against
the expected result, and placing common code for the check under
toolchain/dependencies/. (Heikki Lindholm)
