gdb: rework "set debuginfod" commands

As discussed here [1], do some re-work in the "set debuginfod commands".

First, use "set debuginfod enabled on/off/ask" instead of "set
debuginfod on/off/ask".  This is more MI-friendly, and it gives an
output that makes more sense in "info set", for example.

Then, make the show commands not call "error" when debuginfod support is
not compiled in.  This makes the commands "show" and "show debuginfod"
stop early, breaking gdb.base/default.exp:

    Running /home/smarchi/src/binutils-gdb/gdb/testsuite/gdb.base/default.exp ...
    FAIL: gdb.base/default.exp: info set
    FAIL: gdb.base/default.exp: show

 - Make the "debuginfod enabled" setting default to "off" when debuginfod
   support is not compiled in, and "ask" otherwise.
 - Make the setter of "debuginfod enabled" error out when debuginfod
   support is not compiled in, so that "debuginfod enabled" will always
   remain "off" in that case.
 - Make the setter of "debuginfod verbose" work in any case.  I don't
   see the harm in letting the user change that setting, since the user will
   hit an error if they try to enable the use of debuginfod.
 - I would do the same for the "debuginfod urls" setter, but because
   this one needs to see the DEBUGINFOD_URLS_ENV_VAR macro, provided by
   libdebuginfod, I made that one error out as well if debuginfod
   support is not compiled it (otherwise, I would have left it like
   "debuginfod verbose".  Alternatively, we could hard-code
   "DEBUGINFOD_URLS" in the code (in fact, it was prior to this patch,
   but I think it was an oversight, as other spots use
   DEBUGINFOD_URLS_ENV_VAR), or use a dummy string to store the setting,
   but I don't really see the value in that.

Rename debuginfod_enable to debuginfod_enabled, just so it matches the
setting name.

[1] https://sourceware.org/pipermail/gdb-patches/2021-October/182937.html

Change-Id: I45fdb2993f668226a5639228951362b7800f09d5
Co-Authored-By: Aaron Merey <amerey@redhat.com>

1 files changed, 14 insertions, 13 deletions

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index fc8e5bd..f6d221f 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -47114,27 +47114,28 @@ regarding @code{debuginfod}.
 @value{GDBN} provides the following commands for configuring @code{debuginfod}.
 
 @table @code
-@kindex set debuginfod
-@anchor{set debuginfod}
-@item set debuginfod
-@itemx set debuginfod on
+@kindex set debuginfod enabled
+@anchor{set debuginfod enabled}
+@item set debuginfod enabled
+@itemx set debuginfod enabled on
 @cindex enable debuginfod
 @value{GDBN} will attempt to query @code{debuginfod} servers when missing debug
 info or source files.
 
-@item set debuginfod off
+@item set debuginfod enabled off
 @value{GDBN} will not attempt to query @code{debuginfod} servers when missing
-debug info or source files.  By default, @code{debuginfod} is set to @code{off}
-for non-interactive sessions.
+debug info or source files.  By default, @code{debuginfod enabled} is set to
+@code{off} for non-interactive sessions.
 
-@item set debuginfod ask
+@item set debuginfod enabled ask
 @value{GDBN} will prompt the user to enable or disable @code{debuginfod} before
-attempting to perform the next query.  By default, @code{debuginfod} is set to
-@code{ask} for interactive sessions.
+attempting to perform the next query.  By default, @code{debuginfod enabled}
+is set to @code{ask} for interactive sessions.
 
-@kindex show debuginfod status
-@item show debuginfod status
-Show whether @code{debuginfod} is set to @code{on}, @code{off} or @code{ask}.
+@kindex show debuginfod enabled
+@item show debuginfod enabled
+Display whether @code{debuginfod enabled} is set to @code{on}, @code{off} or
+@code{ask}.
 
 @kindex set debuginfod urls
 @cindex configure debuginfod URLs