46068 (tweaked) (was: github #57): region_highlight: Add memo= support.

This is useful when multiple plugins add region_highlight entries and
subsequently want to remove only their own entries.  Without this
functionality, recognizing one's region_highlight entries is not trivial
because the 'start' and 'end' offsets are modified by editing of $BUFFER
and the highlight specification may not be unique or distinctive.

The tweaks are as follows:

- Change zfree() to zsfree() per workers/46070.

- Remove the mem.c hunk, as it changed the signature of only one out of
  two alternative definitions of zsfree().  (The definition that hunk
  touched is the one that's not used by default.)

1 files changed, 9 insertions, 0 deletions

diff --git a/README b/README
index 8ae615153..9b1b1605f 100644
--- a/README
+++ b/README
@@ -83,6 +83,15 @@ affects you, make the implied colons in the first pattern explicit, as in:
     zstyle ':foo:*:baz:*' style value2
 This will use value1 in both 5.8 and 5.9.
 
+Elements of the region_highlight array have gained a fourth space-separated
+field.  Code written against 5.9 that sets the new field may break under 5.8:
+for example, the element "0 20 bold memo=foo", which is valid under 5.9, would
+not work under 5.8.  (Under the hood, 5.8 does not recognize the space as
+terminating the highlighting specification.)  On the other hand, code that does
+not set the new, fourth field will continue to work under both 5.8 and 5.9.
+(As it happens, adding a comma after "bold" will make both 5.8 and 5.9 do the
+right thing, but this should be viewed as an unsupported hack.)
+
 Incompatibilities between 5.7.1 and 5.8
 ---------------------------------------