Update from gnulib

This incorporates:
2016-05-30 Use GCC_LINT, not lint
2016-05-29 secure_getenv: Port to many more platforms.
* doc/misc/texinfo.tex, lib/secure_getenv.c, lib/verify.h:
* m4/secure_getenv.m4: Copy from gnulib.

4 files changed, 136 insertions, 99 deletions

diff --git a/doc/misc/texinfo.tex b/doc/misc/texinfo.tex
index d7e6b1f6b8..85846f4da4 100644
--- a/doc/misc/texinfo.tex
+++ b/doc/misc/texinfo.tex
@@ -3,7 +3,7 @@
 % Load plain if necessary, i.e., if running under initex.
 \expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi
 %
-\def\texinfoversion{2016-05-26.20}
+\def\texinfoversion{2016-05-28.16}
 %
 % Copyright 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995,
 % 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
@@ -4609,11 +4609,23 @@ end
 % Like \expandablevalue, but completely expandable (the \message in the
 % definition above operates at the execution level of TeX).  Used when
 % writing to auxiliary files, due to the expansion that \write does.
+% If flag is undefined, pass through an unexpanded @value command: maybe it 
+% will be set by the time it is read back in.
 %
 % NB flag names containing - or _ may not work here.
 \def\dummyvalue#1{%
   \expandafter\ifx\csname SET#1\endcsname\relax
-    [No value for ``#1'']%
+    \noexpand\value{#1}%
+  \else
+    \csname SET#1\endcsname
+  \fi
+}
+
+% Used for @value's in index entries to form the sort key: expand the @value
+% if possible, otherwise sort late.
+\def\indexnofontsvalue#1{%
+  \expandafter\ifx\csname SET#1\endcsname\relax
+    ZZZZZZZ
   \else
     \csname SET#1\endcsname
   \fi
@@ -4760,7 +4772,7 @@ end
 
 % Define \doindex, the driver for all index macros.
 % Argument #1 is generated by the calling \fooindex macro,
-% and it the two-letter name of the index.
+% and it is the two-letter name of the index.
 
 \def\doindex#1{\edef\indexname{#1}\parsearg\doindexxxx}
 \def\doindexxxx #1{\doind{\indexname}{#1}}
@@ -4769,6 +4781,7 @@ end
 \def\docodeindex#1{\edef\indexname{#1}\parsearg\docodeindexxxx}
 \def\docodeindexxxx #1{\doind{\indexname}{\code{#1}}}
 
+
 % Used when writing an index entry out to an index file to prevent
 % expansion of Texinfo commands that can appear in an index entry.
 %
@@ -4787,9 +4800,11 @@ end
   \def\}{{\tt\char125}}%
   %
   % Do the redefinitions.
-  \commondummies
+  \definedummies
 }
 
+% Used for the aux and toc files, where @ is the escape character.
+%
 % For the aux and toc files, @ is the escape character.  So we want to
 % redefine everything using @ as the escape character (instead of
 % \realbackslash, still used for index files).  When everything uses @,
@@ -4802,30 +4817,35 @@ end
   \let\} = \rbraceatcmd
   %
   % Do the redefinitions.
-  \commondummies
+  \definedummies
   \otherbackslash
 }
 
-% Called from \indexdummies and \atdummies.
+% \definedummyword defines \#1 as \string\#1\space, thus effectively
+% preventing its expansion.  This is used only for control words,
+% not control letters, because the \space would be incorrect for
+% control characters, but is needed to separate the control word
+% from whatever follows.
 %
-\def\commondummies{%
-  % \definedummyword defines \#1 as \string\#1\space, thus effectively
-  % preventing its expansion.  This is used only for control words,
-  % not control letters, because the \space would be incorrect for
-  % control characters, but is needed to separate the control word
-  % from whatever follows.
-  %
-  % For control letters, we have \definedummyletter, which omits the
-  % space.
-  %
-  % These can be used both for control words that take an argument and
-  % those that do not.  If it is followed by {arg} in the input, then
-  % that will dutifully get written to the index (or wherever).
-  %
-  \def\definedummyword  ##1{\def##1{\string##1\space}}%
-  \def\definedummyletter##1{\def##1{\string##1}}%
-  \let\definedummyaccent\definedummyletter
+% These can be used both for control words that take an argument and
+% those that do not.  If it is followed by {arg} in the input, then
+% that will dutifully get written to the index (or wherever).
+%
+% For control letters, we have \definedummyletter, which omits the
+% space.
+%
+\def\definedummyword  #1{\def#1{\string#1\space}}%
+\def\definedummyletter#1{\def#1{\string#1}}%
+\let\definedummyaccent\definedummyletter
+
+% Called from \indexdummies and \atdummies, to effectively prevent
+% the expansion of commands.
+%
+\def\definedummies{%
   %
+  \let\commondummyword\definedummyword
+  \let\commondummyletter\definedummyletter
+  \let\commondummyaccent\definedummyaccent
   \commondummiesnofonts
   %
   \definedummyletter\_%
@@ -4910,77 +4930,77 @@ end
   \normalturnoffactive
 }
 
-% \commondummiesnofonts: common to \commondummies and \indexnofonts.
-% Define \definedumyletter, \definedummyaccent and \definedummyword before
-% using.
+% \commondummiesnofonts: common to \definedummies and \indexnofonts.
+% Define \commondummyletter, \commondummyaccent and \commondummyword before
+% using.  Used for accents, font commands, and various control letters.
 %
 \def\commondummiesnofonts{%
   % Control letters and accents.
-  \definedummyletter\!%
-  \definedummyaccent\"%
-  \definedummyaccent\'%
-  \definedummyletter\*%
-  \definedummyaccent\,%
-  \definedummyletter\.%
-  \definedummyletter\/%
-  \definedummyletter\:%
-  \definedummyaccent\=%
-  \definedummyletter\?%
-  \definedummyaccent\^%
-  \definedummyaccent\`%
-  \definedummyaccent\~%
-  \definedummyword\u
-  \definedummyword\v
-  \definedummyword\H
-  \definedummyword\dotaccent
-  \definedummyword\ogonek
-  \definedummyword\ringaccent
-  \definedummyword\tieaccent
-  \definedummyword\ubaraccent
-  \definedummyword\udotaccent
-  \definedummyword\dotless
+  \commondummyletter\!%
+  \commondummyaccent\"%
+  \commondummyaccent\'%
+  \commondummyletter\*%
+  \commondummyaccent\,%
+  \commondummyletter\.%
+  \commondummyletter\/%
+  \commondummyletter\:%
+  \commondummyaccent\=%
+  \commondummyletter\?%
+  \commondummyaccent\^%
+  \commondummyaccent\`%
+  \commondummyaccent\~%
+  \commondummyword\u
+  \commondummyword\v
+  \commondummyword\H
+  \commondummyword\dotaccent
+  \commondummyword\ogonek
+  \commondummyword\ringaccent
+  \commondummyword\tieaccent
+  \commondummyword\ubaraccent
+  \commondummyword\udotaccent
+  \commondummyword\dotless
   %
   % Texinfo font commands.
-  \definedummyword\b
-  \definedummyword\i
-  \definedummyword\r
-  \definedummyword\sansserif
-  \definedummyword\sc
-  \definedummyword\slanted
-  \definedummyword\t
+  \commondummyword\b
+  \commondummyword\i
+  \commondummyword\r
+  \commondummyword\sansserif
+  \commondummyword\sc
+  \commondummyword\slanted
+  \commondummyword\t
   %
   % Commands that take arguments.
-  \definedummyword\abbr
-  \definedummyword\acronym
-  \definedummyword\anchor
-  \definedummyword\cite
-  \definedummyword\code
-  \definedummyword\command
-  \definedummyword\dfn
-  \definedummyword\dmn
-  \definedummyword\email
-  \definedummyword\emph
-  \definedummyword\env
-  \definedummyword\file
-  \definedummyword\image
-  \definedummyword\indicateurl
-  \definedummyword\inforef
-  \definedummyword\kbd
-  \definedummyword\key
-  \definedummyword\math
-  \definedummyword\option
-  \definedummyword\pxref
-  \definedummyword\ref
-  \definedummyword\samp
-  \definedummyword\strong
-  \definedummyword\tie
-  \definedummyword\U
-  \definedummyword\uref
-  \definedummyword\url
-  \definedummyword\var
-  \definedummyword\verb
-  \definedummyword\w
-  \definedummyword\xref
+  \commondummyword\abbr
+  \commondummyword\acronym
+  \commondummyword\anchor
+  \commondummyword\cite
+  \commondummyword\code
+  \commondummyword\command
+  \commondummyword\dfn
+  \commondummyword\dmn
+  \commondummyword\email
+  \commondummyword\emph
+  \commondummyword\env
+  \commondummyword\file
+  \commondummyword\image
+  \commondummyword\indicateurl
+  \commondummyword\inforef
+  \commondummyword\kbd
+  \commondummyword\key
+  \commondummyword\math
+  \commondummyword\option
+  \commondummyword\pxref
+  \commondummyword\ref
+  \commondummyword\samp
+  \commondummyword\strong
+  \commondummyword\tie
+  \commondummyword\U
+  \commondummyword\uref
+  \commondummyword\url
+  \commondummyword\var
+  \commondummyword\verb
+  \commondummyword\w
+  \commondummyword\xref
 }
 
 % For testing: output @{ and @} in index sort strings as \{ and \}.
@@ -5036,11 +5056,11 @@ end
 %
 \def\indexnofonts{%
   % Accent commands should become @asis.
-  \def\definedummyaccent##1{\let##1\asis}%
+  \def\commondummyaccent##1{\let##1\asis}%
   % We can just ignore other control letters.
-  \def\definedummyletter##1{\let##1\empty}%
+  \def\commondummyletter##1{\let##1\empty}%
   % All control words become @asis by default; overrides below.
-  \let\definedummyword\definedummyaccent
+  \let\commondummyword\commondummyaccent
   \commondummiesnofonts
   %
   % Don't no-op \tt, since it isn't a user-level command
@@ -5125,8 +5145,11 @@ end
   % goes to end-of-line is not handled.
   %
   \macrolist
+  \let\value\indexnofontsvalue
 }
 
+
+
 
 \let\SETmarginindex=\relax % put index entries in margin (undocumented)?
 
diff --git a/lib/secure_getenv.c b/lib/secure_getenv.c
index f359ab2173..88a60dc33c 100644
--- a/lib/secure_getenv.c
+++ b/lib/secure_getenv.c
@@ -1,4 +1,4 @@
-/* Look up an environment variable more securely.
+/* Look up an environment variable, returning NULL in insecure situations.
 
    Copyright 2013-2016 Free Software Foundation, Inc.
 
@@ -20,22 +20,35 @@
 #include <stdlib.h>
 
 #if !HAVE___SECURE_GETENV
-# if HAVE_ISSETUGID
+# if HAVE_ISSETUGID || (HAVE_GETUID && HAVE_GETEUID && HAVE_GETGID && HAVE_GETEGID)
 #  include <unistd.h>
-# else
-#  undef issetugid
-#  define issetugid() 1
 # endif
 #endif
 
 char *
 secure_getenv (char const *name)
 {
-#if HAVE___SECURE_GETENV
+#if HAVE___SECURE_GETENV /* glibc */
   return __secure_getenv (name);
-#else
+#elif HAVE_ISSETUGID /* OS X, FreeBSD, NetBSD, OpenBSD */
   if (issetugid ())
-    return 0;
+    return NULL;
+  return getenv (name);
+#elif HAVE_GETUID && HAVE_GETEUID && HAVE_GETGID && HAVE_GETEGID /* other Unix */
+  if (geteuid () != getuid () || getegid () != getgid ())
+    return NULL;
   return getenv (name);
+#elif (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ /* native Windows */
+  /* On native Windows, there is no such concept as setuid or setgid binaries.
+     - Programs launched as system services have high privileges, but they don't
+       inherit environment variables from a user.
+     - Programs launched by a user with "Run as Administrator" have high
+       privileges and use the environment variables, but the user has been asked
+       whether he agrees.
+     - Programs launched by a user without "Run as Administrator" cannot gain
+       high privileges, therefore there is no risk. */
+  return getenv (name);
+#else
+  return NULL;
 #endif
 }
diff --git a/lib/verify.h b/lib/verify.h
index 2f4383743b..5c8381d290 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -263,7 +263,7 @@ template <int w>
 # define assume(R) ((R) ? (void) 0 : __builtin_unreachable ())
 #elif 1200 <= _MSC_VER
 # define assume(R) __assume (R)
-#elif (defined lint \
+#elif ((defined GCC_LINT || defined lint) \
        && (__has_builtin (__builtin_trap) \
            || 3 < __GNUC__ + (3 < __GNUC_MINOR__ + (4 <= __GNUC_PATCHLEVEL__))))
   /* Doing it this way helps various packages when configured with
diff --git a/m4/secure_getenv.m4 b/m4/secure_getenv.m4
index 00194c8497..3983173603 100644
--- a/m4/secure_getenv.m4
+++ b/m4/secure_getenv.m4
@@ -22,4 +22,5 @@ AC_DEFUN([gl_PREREQ_SECURE_GETENV], [
   if test $ac_cv_func___secure_getenv = no; then
     AC_CHECK_FUNCS([issetugid])
   fi
+  AC_CHECK_FUNCS_ONCE([getuid geteuid getgid getegid])
 ])