doc: fix bad @xref uses

Upstream gnulib maint.mk improvements caught a few issues we
should fix, as well as a few issues in files we copy from
other sources that we will just ignore here.

* doc/autoconf.texi (Generic Programs, Special Shell Variables)
(Limitations of Builtins): Use references correctly.
* cfg.mk
(exclude_file_name_regexp--sc_prohibit_undesirable_word_seq)
(exclude_file_name_regexp--sc_useless_cpp_parens): Add exemptions.

2 files changed, 8 insertions, 7 deletions

diff --git a/cfg.mk b/cfg.mk
index 3febab07..e79ff556 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -129,12 +129,13 @@ update-copyright-env = \
 # Prevent incorrect NEWS edits.
 old_NEWS_hash = 54ad39275441a2a3fcbe6182da4f84fb
 
-exclude_file_name_regexp--sc_prohibit_undesirable_word_seq = ^maint\.mk$$
+exclude_file_name_regexp--sc_prohibit_undesirable_word_seq = \
+  ^(maint\.mk|build-aux/texinfo\.tex)$$
 exclude_file_name_regexp--sc_prohibit_test_minus_ao = \
   ^(maint\.mk|doc/autoconf\.texi)$$
-
 exclude_file_name_regexp--sc_prohibit_atoi_atof = ^doc/autoconf\.texi$$
-exclude_file_name_regexp--sc_useless_cpp_parens = ^build-aux/config\.guess$$
+exclude_file_name_regexp--sc_useless_cpp_parens = \
+  ^(build-aux/config\.guess|doc/standards\.texi)$$
 exclude_file_name_regexp--sc_trailing_blank = ^build-aux/texinfo\.tex$$
 exclude_file_name_regexp--sc_two_space_separator_in_usage = \
   ^build-aux/gnupload$$
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index a6296689..34ca2137 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -4211,7 +4211,7 @@ AC_PATH_PROG([INETD], [inetd], [/usr/libexec/inetd],
 @end example
 
 You are strongly encouraged to declare the @var{variable} passed to
-@code{AC_CHECK_PROG} etc.@: as precious, @xref{Setting Output Variables},
+@code{AC_CHECK_PROG} etc.@: as precious.  @xref{Setting Output Variables},
 @code{AC_ARG_VAR}, for more details.
 
 @anchor{AC_CHECK_PROG}
@@ -16782,7 +16782,7 @@ PS4='+ '
 
 @noindent
 (actually, there is some complication due to bugs in @command{unset};
-see @pxref{unset, , Limitations of Shell Builtins}).
+@pxref{unset, , Limitations of Shell Builtins}).
 
 @item FPATH
 @evindex FPATH
@@ -17874,8 +17874,8 @@ for an @command{echo} that does not interpret @samp{\} or leading
 @samp{-}. With Solaris @command{ksh}, it is possible to use @code{print
 -r --} for this role instead.
 
-For a discussion of portable alternatives to both @command{printf}
-and @command{echo}, @xref{echo, , Limitations of Shell Builtins}.
+@xref{echo, , Limitations of Shell Builtins} for a discussion of
+portable alternatives to both @command{printf} and @command{echo}.
 
 
 @item @command{pwd}