[PATCH 8/8] Require readline 7 or newer

[Tom Tromey <tom@tromey.com>]

This changes gdb to require readline 7 or newer at build time.

2019-04-21  Tom Tromey  <tom@tromey.com>

	* README: Update.
	* event-top.c: Require readline 7.

gdb/doc/ChangeLog
2019-04-21  Tom Tromey  <tom@tromey.com>

	* gdb.texinfo (Configure Options): Document minimum version of
	readline.
---
 gdb/ChangeLog       | 5 +++++
 gdb/README          | 3 ++-
 gdb/doc/ChangeLog   | 5 +++++
 gdb/doc/gdb.texinfo | 3 ++-
 gdb/event-top.c     | 3 +++
 5 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/gdb/README b/gdb/README
index 8a91aab2a4c..8883a8a09e3 100644
--- a/gdb/README
+++ b/gdb/README
@@ -439,7 +439,8 @@ more obscure GDB `configure' options are not listed here.
 
 `--with-system-readline'
      Use the readline library installed on the host, rather than the
-     library supplied as part of GDB.
+     library supplied as part of GDB.  Readline 7 or newer is required;
+     this is enforced by the build system.
 
 `--with-system-zlib
      Use the zlib library installed on the host, rather than the
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 89b1eda2c17..e384718fc11 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -36897,7 +36897,8 @@ details.
 
 @item --with-system-readline
 Use the readline library installed on the host, rather than the
-library supplied as part of @value{GDBN}.
+library supplied as part of @value{GDBN}.  Readline 7 or newer is
+required; this is enforced by the build system.
 
 @item --with-system-zlib
 Use the zlib library installed on the host, rather than the library
diff --git a/gdb/event-top.c b/gdb/event-top.c
index 2132fb550dc..07cedc42584 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -48,6 +48,9 @@
 /* readline defines this.  */
 #undef savestring
 
+/* gdb requires readline 7 now.  */
+gdb_static_assert (RL_VERSION_MAJOR >= 7);
+
 static std::string top_level_prompt ();
 
 /* Signal handlers.  */
-- 
2.17.2