gdb: remove --disable-gdbmi configure option

I noticed that the --disable-gdbmi option was broken for almost a year
(since 740b42ceb7c "gdb/python/mi: create MI commands using python").

The problem today is the python/py-cmd.c file.  It is included in the
build if Python support is enabled, and it calls into some MI functions
(e.g. insert_mi_cmd_entry).  If MI support is disabled, we get some
undefined symbols like:

    mold: error: undefined symbol: insert_mi_cmd_entry(std::unique_ptr<mi_command, std::default_delete<mi_command> >)
    >>> referenced by py-micmd.c
    >>>               python/py-micmd.o:(micmdpy_install_command(micmdpy_object*))

The python/py-cmd.c file should be included in the build if both Python
and MI support are enabled.  It is not a case we support today, but it
could be done with a bit more configure code.  However, I think we
should just remove the --disable-gdbmi option, and just include MI
support unconditionally.

Tom Tromey proposed a while ago to remove this option, but it ended
staying:

  https://inbox.sourceware.org/gdb-patches/20180628172132.28843-1-tom@tromey.com/

However, there was no strong opposition to remove it.  The argument was
just "bah, it doesn't hurt anybody".

But given today's case, I would rather remove complexity rather than add
some.  I couldn't find anybody caring deeply for that option, and it's
not like MI adds any external dependency.  It's just a bit more code.

Removing the option will not break anybody using --disable-gdbmi (it can
be found in many build scripts [1]), since we don't flag invalid
configure flags.

So, remove the option from configure.ac, and adjust Makefile.in
accordingly to always include the MI objects in the build.

[1] https://github.com/search?q=%22--disable-gdbmi%22&type=code

Change-Id: Ifcaa8c9fc4abc6fa686ed5fd984598644f745240
Approved-By: Tom Tromey <tom@tromey.com>

1 files changed, 2 insertions, 29 deletions

diff --git a/gdb/configure b/gdb/configure
index 6bce5c7..017ec05 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -913,7 +913,6 @@ with_auto_load_safe_path
 enable_targets
 enable_64_bit_bfd
 with_amd_dbgapi
-enable_gdbmi
 enable_tui
 enable_gdbtk
 with_debuginfod
@@ -1630,7 +1629,6 @@ Optional Features:
   --enable-targets=TARGETS
                           alternative target configurations
   --enable-64-bit-bfd     64-bit support (on hosts with narrower word sizes)
-  --disable-gdbmi         disable machine-interface (MI)
   --enable-tui            enable full-screen terminal user interface (TUI)
   --enable-gdbtk          enable gdbtk graphical user interface (GUI)
   --enable-profiling      enable profiling of GDB
@@ -11450,7 +11448,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11453 "configure"
+#line 11451 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11556,7 +11554,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11559 "configure"
+#line 11557 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -18304,31 +18302,6 @@ _ACEOF
 
 fi
 
-# Enable MI.
-# Check whether --enable-gdbmi was given.
-if test "${enable_gdbmi+set}" = set; then :
-  enableval=$enable_gdbmi;
-	   case $enableval in
-	     yes | no)
-	       ;;
-	     *)
-	       as_fn_error $? "bad value $enableval for --enable-gdbmi" "$LINENO" 5
-	       ;;
-	   esac
-
-else
-  enable_gdbmi=yes
-fi
-
-if test x"$enable_gdbmi" = xyes; then
-  if test -d "$srcdir/mi"; then
-    CONFIG_OBS="$CONFIG_OBS \$(SUBDIR_MI_OBS)"
-    CONFIG_DEPS="$CONFIG_DEPS \$(SUBDIR_MI_DEPS)"
-    CONFIG_SRCS="$CONFIG_SRCS \$(SUBDIR_MI_SRCS)"
-    ENABLE_CFLAGS="$ENABLE_CFLAGS \$(SUBDIR_MI_CFLAGS)"
-  fi
-fi
-
 # Enable TUI.
 # Check whether --enable-tui was given.
 if test "${enable_tui+set}" = set; then :