'sed -e' dumps core

[Paul Eggert]

Richard A. O'Keefe writes that "sed -e" dumps core in older SunOS releases, but
not on SunOS 4.0RRBeta2 on a 386i.  This prompts me to dig out the following
bug report for SunOS 4.0 on a Sun-3/60 (Sun bug ID 1012595):

sed: "-e '' file" and "-f /dev/null file" treat the file name as a command
	When sed is given an empty script with the -e or -f flag, it gets
	confused and tries to grab the next argument as a command.
	The following script illustrates the problem.  All three commands
	should do nothing, but only the first one works correctly.

		% sed '' /dev/null
		% sed -e '' /dev/null
		sed: Extra text at end of command: /dev/null
		% sed -f /dev/null /dev/null
		sed: Extra text at end of command: /dev/null

This new bug does not exist under SunOS 3.5 on the same machine; 3.5 exhibited
the old core dumping bug.  So if you're fixing the "'sed -e' dumps core" bug,
please check that you do not introduce this new bug, like Sun did.