Apply some improvements suggested by Mike Frysinger.

These improvements were suggested at https://savannah.gnu.org/bugs/?46714.
* find/Makefile.am (check_PROGRAMS): Put oldfind in check_PROGRAMS
instead of noinst_PROGRAMS, so that we don't build it when it is
not needed.
* m4/withfts.m4 (FIND_WITH_FTS): Fix whitespace alignment.
(FIND_WITH_FTS): The WITH_FTS C preprocessor macro and the
accompanying Automake conditional are no longer needed.
* THANKS: Add Mike Frysinger.

THANKS

@@ -34,6 +34,7 @@ Mark Kettenis <kettenis@gnu.org>
 Martin Buchholz
 Matt Mueller <donut@azstarnet.com>
 Michael Haubenwallner <michael.haubenwallner@salomon.at>
+Mike Frysinger <vapier@gentoo.org>
 Nelson Beebe
 Nigel Stepp <stepp@atistart.net>
 Nix <nix@esperi.org.uk>

find/Makefile.am

@@ -9,7 +9,7 @@ libfindtools_a_SOURCES = finddata.c fstype.c parser.c pred.c exec.c tree.c util.
 # one without (called "oldfind").  The oldfind binary is no longer
 # installed.
 bin_PROGRAMS     = find
-noinst_PROGRAMS = oldfind
+check_PROGRAMS   = oldfind
 find_SOURCES     = ftsfind.c
 oldfind_SOURCES  = oldfind.c
 man_MANS         = find.1

m4/withfts.m4

@@ -9,6 +9,4 @@ AC_DEFUN([FIND_WITH_FTS],
 	no)	AC_MSG_ERROR([Using --without-fts is not longer supported]) ;;
         *) AC_MSG_ERROR([Invalid value for --with-fts: $with_fts])
   esac
-  AM_CONDITIONAL(WITH_FTS, [[test x"${with_fts-no}" != xno]])
-  AC_DEFINE([WITH_FTS], 1, [Define if you want to use fts() to do the filesystem search.])
 ])