Add --without-makeinfo

Currently, we cannot build gdb without makeinfo installed.

It would be convenient to work around this by using the configure flag
MAKEINFO=/usr/bin/true or some such, but that doesn't work because top-level
configure requires a makeinfo of at least version 4.7, and that version check
fails for /usr/bin/true, so we end up with MAKEINFO=missing instead.

What does work is this:
...
$ ./configure
$ make MAKEINFO=/usr/bin/true
...
but the drawback is that it'll have to be specified for each make invocation.

Fix this by adding support for --without-makeinfo in top-level configure.

Tested by building gdb on x86_64-linux, and verifying that no .info files
were generated.

ChangeLog:

2022-09-05  Tom de Vries  <tdevries@suse.de>

	* configure.ac: Add --without-makeinfo.
	* configure: Regenerate.

---
 configure    | 4 ++++
 configure.ac | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/configure b/configure
index 16139e3bfa3..66ccef4d8c0 100755
--- a/configure
+++ b/configure
@@ -8386,6 +8386,9 @@ fi
 done
 test -n "$MAKEINFO" || MAKEINFO="$MISSING makeinfo"
 
+if test $with_makeinfo = "no"; then
+MAKEINFO=true
+else
 case " $build_configdirs " in
   *" texinfo "*) MAKEINFO='$$r/$(BUILD_SUBDIR)/texinfo/makeinfo/makeinfo' ;;
   *)
@@ -8401,6 +8404,7 @@ case " $build_configdirs " in
     ;;
 
 esac
+fi
 
 # FIXME: expect and dejagnu may become build tools?
 
diff --git a/configure.ac b/configure.ac
index a5555a9c91b..3680fa97087 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3436,6 +3436,9 @@ case " $build_configdirs " in
 esac
 
 AC_CHECK_PROGS([MAKEINFO], makeinfo, [$MISSING makeinfo])
+if test $with_makeinfo = "no"; then
+MAKEINFO=true
+else
 case " $build_configdirs " in
   *" texinfo "*) MAKEINFO='$$r/$(BUILD_SUBDIR)/texinfo/makeinfo/makeinfo' ;;
   *)
@@ -3451,6 +3454,7 @@ changequote(,)
     ;;
 changequote([,])
 esac
+fi
 
 # FIXME: expect and dejagnu may become build tools?