Deprecate the use of regexp.h

<regexp.h> (not to be confused with <regex.h>) is an obsolete and
frankly horrible regular expression-matching API.  It was part of SVID
but was withdrawn in Issue 5 (for reference, we're on Issue 7 now).
It doesn't do anything you can't do with <regex.h>, and using it
involves defining a bunch of macros before including the header.
Moreover, the code in regexp.h that uses those macros has been buggy
since its creation (in 1996) and no one has noticed, which indicates
to me that there are no users.  (Specifically, RETURN() is used in a
whole bunch of cases where it should have been ERROR().)

The header is given a warning and marked deprecated for 2.22.

See:
https://sourceware.org/ml/libc-alpha/2015-07/msg00862.html and
https://sourceware.org/ml/libc-alpha/2015-07/msg00871.html.

1 files changed, 8 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 3956263b0e..1179f92b52 100644
--- a/NEWS
+++ b/NEWS
@@ -79,6 +79,14 @@ Version 2.22
 
 * Port to Native Client running on ARMv7-A (--host=arm-nacl).
   Contributed by Roland McGrath (Google).
+
+* The header <regexp.h> is deprecated, and will be removed in a future
+  release.  Use of this header will trigger a deprecation warning.
+  Application developers should update their code to use <regex.h> instead.
+
+  This header was formerly part of SUSv2, but was deprecated in 1997 and
+  removed from the standard in 2001.  Also, the glibc implementation
+  leaks memory.  See BZ#18681 for more details.
 
 Version 2.21