[patch+7.4] Fix 7.4 build regression by me requiring makeinfo (PR build/13638)

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

http://sourceware.org/bugzilla/show_bug.cgi?id=13638

With 7.3.1 you could do `./configure; make' even without makeinfo.
With 7.4 with `./configure; make' you get:
configure: error: makeinfo is required for compilation

Joel caught this before
http://sourceware.org/ml/gdb-patches/2011-10/msg00655.html
but unfortunately I thought makeinfo is really required being used from the
CVS/GIT builds.

For CVS/GIT builds makeinfo has always been required.
But for releases makeinfo was not required.  It is now required by gdb-7.4.

The current code of mine is wrong anyway, topdir/configure.ac has some more
complicated logic for makeinfo detection.  It is enough to just have its
result by AC_ARG_VAR instead of trying to duplicate the topdir/configure.ac
work.

MAKEINFOFLAGS is currently not passed from topdir/configure.ac|Makefile*, it
is merged in MAKEINFO.  topdir/ should be fixed in the future.  MAKEINFOFLAGS
has no passed value now but removing it from gdb/configure.ac would mean also
removing it from gdb/**/Makefile.in while in fact it should be there for the
future topdir/ fix.

There is another issue that GDB build from CVS/GIT should detect early enough
the missing tools (like bison/flex) than mysteriously failing afterwards.
But I think this issue should not be mixed with this one.  Also it is
unrelated to the 7.4-branch which needs this fix.

I will check it in, still posting first as it is configury magic.


Thanks,
Jan


gdb/
2012-02-09  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR build/13638
	* configure.ac (MAKEINFO): Replace AC_CHECK_PROG by AC_ARG_VAR.
	(MAKEINFOFLAGS): Replace static string by AC_ARG_VAR.
	* configure: Regenerate.

--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -85,24 +85,12 @@ PACKAGE=gdb
 AC_DEFINE_UNQUOTED(PACKAGE, "$PACKAGE", [Name of this package. ])
 AC_SUBST(PACKAGE)
 
-# Do we have a single-tree copy of texinfo?  Even if we do, we can't
-# rely on it - libiberty is built before texinfo.
-AC_CHECK_PROG(MAKEINFO, makeinfo, makeinfo, )
-if test "x$MAKEINFO" = "x"; then
-  AC_ERROR([makeinfo is required for compilation])
-else
-  case "$MAKEINFO" in
-    */missing\ makeinfo*)
-      AC_ERROR([makeinfo is required for compilation])
-      ;;
-  esac
-fi
-AC_SUBST(MAKEINFO)
-
-# --split-size=5000000 may be already in $MAKEINFO from parent configure.
-# Re-running configure in gdb/ would lose it so ensure it stays present.
-MAKEINFOFLAGS=${MAKEINFOFLAGS---split-size=5000000}
-AC_SUBST(MAKEINFOFLAGS)
+# We never need to detect it in this sub-configure.
+# But preserve it for config.status --recheck.
+AC_ARG_VAR(MAKEINFO,
+  [Parent configure detects if it is of sufficient version.])
+AC_ARG_VAR(MAKEINFOFLAGS,
+  [Parameters for MAKEINFO.])
 
 MAKEINFO_EXTRA_FLAGS=""
 AC_CACHE_CHECK([whether $MAKEINFO supports @click], gdb_cv_have_makeinfo_click,