Minor fixups for AC_TYPE_SIZE_T obsolescence

Move its doc to “Obsolete Macros” section, and reword.
Omit newly-inserted newline at start of AC_FUNC_ALLOC definiens.

NEWS

diff --git a/NEWS b/NEWS
index 8a8ad79..b5636f7 100644
--- a/NEWS
+++ b/NEWS
@@ -11,8 +11,7 @@
   generally useful.
 
 ** Newly obsolete macros
-   The following macro has been marked obsolete. We have no current
-   plans to remove it.
+  The following macro has been marked obsolete, though it still works.
 
        AC_TYPE_SIZE_T
 

doc/autoconf.texi

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 5a8901e..997b3a3 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -6947,20 +6947,6 @@
 This macro caches its result in the @code{ac_cv_type_pid_t} variable.
 @end defmac
 
-@anchor{AC_TYPE_SIZE_T}
-@defmac AC_TYPE_SIZE_T
-@acindex{TYPE_SIZE_T}
-@cvindex size_t
-@caindex type_size_t
-Define @code{size_t} to a suitable type, if standard headers do not
-define it.
-
-This macro caches its result in the @code{ac_cv_type_size_t} variable.
-
-This macro is obsolescent, nowadays it is safe to assume the facilities of C89
-exist.
-@end defmac
-
 @defmac AC_TYPE_SSIZE_T
 @acindex{TYPE_SSIZE_T}
 @cvindex ssize_t
@@ -24539,6 +24525,16 @@
 without needing to use this macro or @code{RETSIGTYPE}.
 @end defmac
 
+@anchor{AC_TYPE_SIZE_T}
+@defmac AC_TYPE_SIZE_T
+@acindex{TYPE_SIZE_T}
+@cvindex size_t
+@caindex type_size_t
+Define @code{size_t} to a suitable type, if standard headers do not define it.
+Cache the result in the @code{ac_cv_type_size_t} variable.
+These days it is portable to assume C89 without using this macro.
+@end defmac
+
 @defmac AC_UID_T
 @acindex{UID_T}
 Replaced by @code{AC_TYPE_UID_T} (@pxref{AC_TYPE_UID_T}).

lib/autoconf/functions.m4

diff --git a/lib/autoconf/functions.m4 b/lib/autoconf/functions.m4
index 097469a..6bbcad3 100644
--- a/lib/autoconf/functions.m4
+++ b/lib/autoconf/functions.m4
@@ -410,8 +410,8 @@
 # --------------
 AN_FUNCTION([alloca], [AC_FUNC_ALLOCA])
 AN_HEADER([alloca.h], [AC_FUNC_ALLOCA])
-AC_DEFUN([AC_FUNC_ALLOCA], [
-# The Ultrix 4.2 mips builtin alloca declared by alloca.h only works
+AC_DEFUN([AC_FUNC_ALLOCA],
+[# The Ultrix 4.2 mips builtin alloca declared by alloca.h only works
 # for constant arguments.  Useless!
 AC_CACHE_CHECK([for working alloca.h], ac_cv_working_alloca_h,
 [AC_LINK_IFELSE(