diff --git a/NEWS b/NEWS
index 2eec4333..6166bd64 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,7 @@ Major changes in release 2.0:
 * AC_CHECK_TYPE, which checks whether sys/types.h defines a given type.
 * AC_TRY_LINK, which obsoletes AC_COMPILE_CHECK.
 * AC_PREFIX_PROGRAM, which obsoletes AC_PREFIX.
+* AC_HEADER_DIRENT, which obsoletes AC_DIR_HEADER.
 * AC_ARG_ENABLE and AC_ARG_WITH, which obsolete AC_ENABLE and AC_WITH.
 * AC_SUBST_FILE, to insert one file into another.
 
@@ -30,8 +31,6 @@ Major changes in release 2.0:
   override the file name "config.status".
 * AC_PROG_INSTALL looks for install.sh in the directory specified by
   AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or srcdir/../.. by default.
-* AC_HEADER_DIRENT (formerly AC_DIR_HEADER) defines standard macro
-  names as well as the old ones, e.g. HAVE_DIRENT_H as well as DIRENT.
 
 ** New utilities:
 * autoscan to generate a preliminary configure.in for a package by
diff --git a/acgeneral.m4 b/acgeneral.m4
index 466abb60..a4ca79f2 100644
--- a/acgeneral.m4
+++ b/acgeneral.m4
@@ -807,7 +807,8 @@ dnl shell variable, so we need the eval.
 dnl if test "${$1+set}" = set; then
 if eval "test \"`echo '${'$1'+set}'`\" = set"; then
 dnl This verbose message is just for testing the caching code.
-  AC_MSG_RESULT(using cached value for $1)
+dnl  AC_MSG_RESULT(using cached value for $1)
+  AC_MSG_RESULT(using cached value)
 else
   $2
 fi
diff --git a/acspecific.m4 b/acspecific.m4
index 4b2aa0e3..41ce7008 100644
--- a/acspecific.m4
+++ b/acspecific.m4
@@ -432,6 +432,7 @@ dnl
 define(AC_HEADER_DIRENT,
 [AC_PROVIDE([$0])dnl
 AC_MSG_CHECKING(for directory library header)
+dnl We don't use AC_CHECK_HEADERS so we can stop when we get a match.
 AC_CACHE_VAL(ac_cv_header_dir,
 [ac_cv_header_dir=no
 for ac_hdr in dirent.h sys/ndir.h sys/dir.h ndir.h; do
@@ -1696,7 +1697,7 @@ fi
 ])dnl
 dnl
 define(AC_OS_XENIX,
-[AC_REQUIRE([AC_HEADER_DIRENT])dnl
+[AC_REQUIRE([AC_DIR_HEADER])dnl
 AC_MSG_CHECKING(for Xenix)
 AC_EGREP_CPP(yes,
 [#if defined(M_XENIX) && !defined(M_UNIX)
diff --git a/autoconf.texi b/autoconf.texi
index b8f60f85..ea6456ea 100644
--- a/autoconf.texi
+++ b/autoconf.texi
@@ -1608,8 +1608,8 @@ by a signal, define @code{HAVE_RESTARTABLE_SYSCALLS}.
 
 The following macros check for certain operating systems that need
 special treatment for some programs, due to exceptional oddities in
-their header files or libraries.  These macros are kludges; they should
-be replaced someday with a more systematic approach, based either on the
+their header files or libraries.  These macros are warts; they should
+be replaced by a more systematic approach, based either on the
 functions they make available or the environments they provide.
 
 @defmac AC_OS_AIX
@@ -1667,8 +1667,8 @@ Used to get @code{strftime}.  It must be called before checking for
 @maindex OS_XENIX
 If on Xenix, add @samp{-lx} to @code{make} variable @code{LIBS}.  Also,
 if @file{sys/ndir.h} is not being used, add @samp{-ldir} to @code{LIBS}.
-Needed when using the directory reading functions.  This macro must be
-called after @code{AC_HEADER_DIRENT}.
+Needed when using the directory reading functions.  This macro calls
+@code{AC_DIR_HEADER} if it has not been called already.
 @end defmac
 
 @node General Purpose Macros, Manual Configuration, Specific Tests, Top
diff --git a/autoheader.in b/autoheader.in
index 3c8f3955..9a3c6d8d 100644
--- a/autoheader.in
+++ b/autoheader.in
@@ -147,7 +147,10 @@ eval "`echo \"$frob\" \
 test -n "$print_version" && exit 0
 
 # Make SYMS newline-separated rather than blank-separated, and remove dups.
-syms="`for sym in $syms; do echo $sym; done | sort | uniq`"
+# Start each symbol with a blank (to match the blank after "#undef")
+# to reduce the possibility of mistakenly matching another symbol that
+# is a substring of it.
+syms="`for sym in $syms; do echo $sym; done | sort | uniq | sed 's@^@ @'`"
 
 if test $# -eq 0; then
   tmpout=autoh$$
@@ -161,7 +164,7 @@ echo "/* ${config_h}.in.  Generated automatically from $infile by autoheader.  *
 
 test -f ${config_h}.top && cat ${config_h}.top
 
-# This puts each paragraph on its own line, separated by @s.
+# This puts each template paragraph on its own line, separated by @s.
 if test -n "$syms"; then
    # Make sure the boundary of template files is also the boundary
    # of the paragraph.  Extra newlines don't hurt since they will
diff --git a/autoheader.sh b/autoheader.sh
index 3c8f3955..9a3c6d8d 100644
--- a/autoheader.sh
+++ b/autoheader.sh
@@ -147,7 +147,10 @@ eval "`echo \"$frob\" \
 test -n "$print_version" && exit 0
 
 # Make SYMS newline-separated rather than blank-separated, and remove dups.
-syms="`for sym in $syms; do echo $sym; done | sort | uniq`"
+# Start each symbol with a blank (to match the blank after "#undef")
+# to reduce the possibility of mistakenly matching another symbol that
+# is a substring of it.
+syms="`for sym in $syms; do echo $sym; done | sort | uniq | sed 's@^@ @'`"
 
 if test $# -eq 0; then
   tmpout=autoh$$
@@ -161,7 +164,7 @@ echo "/* ${config_h}.in.  Generated automatically from $infile by autoheader.  *
 
 test -f ${config_h}.top && cat ${config_h}.top
 
-# This puts each paragraph on its own line, separated by @s.
+# This puts each template paragraph on its own line, separated by @s.
 if test -n "$syms"; then
    # Make sure the boundary of template files is also the boundary
    # of the paragraph.  Extra newlines don't hurt since they will
diff --git a/bin/autoheader.in b/bin/autoheader.in
index 3c8f3955..9a3c6d8d 100644
--- a/bin/autoheader.in
+++ b/bin/autoheader.in
@@ -147,7 +147,10 @@ eval "`echo \"$frob\" \
 test -n "$print_version" && exit 0
 
 # Make SYMS newline-separated rather than blank-separated, and remove dups.
-syms="`for sym in $syms; do echo $sym; done | sort | uniq`"
+# Start each symbol with a blank (to match the blank after "#undef")
+# to reduce the possibility of mistakenly matching another symbol that
+# is a substring of it.
+syms="`for sym in $syms; do echo $sym; done | sort | uniq | sed 's@^@ @'`"
 
 if test $# -eq 0; then
   tmpout=autoh$$
@@ -161,7 +164,7 @@ echo "/* ${config_h}.in.  Generated automatically from $infile by autoheader.  *
 
 test -f ${config_h}.top && cat ${config_h}.top
 
-# This puts each paragraph on its own line, separated by @s.
+# This puts each template paragraph on its own line, separated by @s.
 if test -n "$syms"; then
    # Make sure the boundary of template files is also the boundary
    # of the paragraph.  Extra newlines don't hurt since they will
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index b8f60f85..ea6456ea 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -1608,8 +1608,8 @@ by a signal, define @code{HAVE_RESTARTABLE_SYSCALLS}.
 
 The following macros check for certain operating systems that need
 special treatment for some programs, due to exceptional oddities in
-their header files or libraries.  These macros are kludges; they should
-be replaced someday with a more systematic approach, based either on the
+their header files or libraries.  These macros are warts; they should
+be replaced by a more systematic approach, based either on the
 functions they make available or the environments they provide.
 
 @defmac AC_OS_AIX
@@ -1667,8 +1667,8 @@ Used to get @code{strftime}.  It must be called before checking for
 @maindex OS_XENIX
 If on Xenix, add @samp{-lx} to @code{make} variable @code{LIBS}.  Also,
 if @file{sys/ndir.h} is not being used, add @samp{-ldir} to @code{LIBS}.
-Needed when using the directory reading functions.  This macro must be
-called after @code{AC_HEADER_DIRENT}.
+Needed when using the directory reading functions.  This macro calls
+@code{AC_DIR_HEADER} if it has not been called already.
 @end defmac
 
 @node General Purpose Macros, Manual Configuration, Specific Tests, Top
diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index 466abb60..a4ca79f2 100644
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -807,7 +807,8 @@ dnl shell variable, so we need the eval.
 dnl if test "${$1+set}" = set; then
 if eval "test \"`echo '${'$1'+set}'`\" = set"; then
 dnl This verbose message is just for testing the caching code.
-  AC_MSG_RESULT(using cached value for $1)
+dnl  AC_MSG_RESULT(using cached value for $1)
+  AC_MSG_RESULT(using cached value)
 else
   $2
 fi
diff --git a/lib/autoconf/specific.m4 b/lib/autoconf/specific.m4
index 4b2aa0e3..41ce7008 100644
--- a/lib/autoconf/specific.m4
+++ b/lib/autoconf/specific.m4
@@ -432,6 +432,7 @@ dnl
 define(AC_HEADER_DIRENT,
 [AC_PROVIDE([$0])dnl
 AC_MSG_CHECKING(for directory library header)
+dnl We don't use AC_CHECK_HEADERS so we can stop when we get a match.
 AC_CACHE_VAL(ac_cv_header_dir,
 [ac_cv_header_dir=no
 for ac_hdr in dirent.h sys/ndir.h sys/dir.h ndir.h; do
@@ -1696,7 +1697,7 @@ fi
 ])dnl
 dnl
 define(AC_OS_XENIX,
-[AC_REQUIRE([AC_HEADER_DIRENT])dnl
+[AC_REQUIRE([AC_DIR_HEADER])dnl
 AC_MSG_CHECKING(for Xenix)
 AC_EGREP_CPP(yes,
 [#if defined(M_XENIX) && !defined(M_UNIX)