readline turns out to be a bit of a stumbling block for the project to
move gdbsupport (and then gdbserver) to the top-level.
The issue is that readline headers are intended to be included with
names like "readline/readline.h". To support this, gdb effectively
adds a -I option pointing to the top-level source directory -- but,
importantly, this option is not used when the system readline is used.
For gdbsupport, a -I option like this would always be needed, but that
in turn would break the system readline case. This was PR build/17077,
fixed in commit a8a5dbcab8.
Previously, we had discussed this on the gdb-patches list in terms of
removing readline from the tree
https://sourceware.org/ml/gdb-patches/2019-09/msg00317.html
However, Eli expressed some concerns, and Joel did as well (off-list).
Given those concerns, and the fact that a patch-free local readline is
relatively new in gdb (it was locally patched for years), I changed my
mind and decided to handle this situation by moving the readline
sources down a level.
That is, upstream readline is now in readline/readline, and the
top-level readline directory just contains the minimal configury
needed to build that.
This fixes the problem because, when gdb unconditionally adds a
-I$(top_srcdir), this will not find readline headers. A separate -I
will be needed instead, which is exactly what's needed for
--with-system-readline.
gdb/ChangeLog
2019-10-23 Tom Tromey <tom@tromey.com>
* Makefile.in (READLINE_DIR): Update.
gdb/doc/ChangeLog
2019-10-23 Tom Tromey <tom@tromey.com>
* Makefile.in (READLINE_DIR): Update.
readline/ChangeLog
2019-10-23 Tom Tromey <tom@tromey.com>
Move old contents to readline/ subdirectory.
* aclocal.m4, configure, configure.ac, .gitignore, Makefile.am,
Makefile.in, README: New files.
Change-Id: Ice156a2ee09ea68722b48f64d97146d7428ea9e4
Chet Ramey
Tom Tromey