V9/cmd/sed/fixedbugs

Since V7:

1) garbage could be compiled into pseudo-sense.
Fix: in sed0.c, function compile, case '\0':
remove continue statement, so the '\0' and '\n'
are treated identically.

2) cc warning messages quieted by adding r[12] specifiers
to all references to union reptr.

3) 2/28/80: H command used a null pointer sometimes.
Fix: initialize hspend = holdsp in main().

4) 10/23/80: Null RE could not be first address of range.
Fixed by moving test for null RE into else after test for
no address (near 160 in sed0.c).

5) 2/8/82: got rid of two warning messages from the compiler.
(Changed rep->negfl to rep->r1.negfl in sed0.c;
ipc->r1.lb1 to ipc->r2.lb1 in sed1.c.)

6) 12/6/82: removed (commented out) debugging code in
sed0.c for unrecognized command. (It had been there since
at latest Jan 30, 1981.)

7) 6/22/83: changed the substitute() function in sed1.c
to fix bugs concerning matches of the empty string.
(The previous version would loop.  Note that /bin/ed
as of today has a different bug relating to s/a*b/x/g;
/usr/rob/bin/qed has a third bug.)
s/a*/x/g should now work properly.

8) 4/12/84: added sed: prefix to all error messages.

9) 6/25/84: Removed an artificial limit on the size of a regular expression
by undefinig ESIZE, and making the test of how big a regular expression
can be always be against reend (= &respace[RESIZE].
This limits the total space for storing re's, instead of limiting them
individually.

10) 4/26/85: Increased the size of PTRSPACE (256->512) and RESPACE
(5000->10000).

11) 5/17/85: fixed a bug found by boulder!geoff;
resets sflag (saying whether a substitution was done on the
current line) in routine gline().
Fixes "t" to work as advertized.

12) 7/24/85: changed the 's' case in fcomp to notice if an empty
RE is the first re found.

13) 10/01/85: increased max number of w files to 120; #defined MAXFILES

14) 10/01/85: fixed number of line-numbers to be 256 instead of 128
	(in sed1.c added & 0377 when line# index is moved from byte
	to int).

15) 4/16/86: changed number of linenumbers to be a long instead of a char.

16) 4/14/86: fixed bug in case '}' in comp() in sed0.c so that ; functions
	as a new-line separating commands.