Merge from gnulib

This incorporates:
2017-07-16 explicit_bzero: new module
2017-07-15 getdtablesize: Add minimal support for OpenVMS.
* lib/getdtablesize.c, lib/string.in.h, m4/getdtablesize.m4:
* m4/string_h.m4:
Copy from Gnulib.
* lib/gnulib.mk.in: Regenerate.

lib/getdtablesize.c

@@ -1,4 +1,4 @@
-/* getdtablesize() function for platforms that don't have it.
+/* getdtablesize() function: Return maximum possible file descriptor value + 1.
    Copyright (C) 2008-2017 Free Software Foundation, Inc.
    Written by Bruno Haible <bruno@clisp.org>, 2008.
 

lib/gnulib.mk.in

@@ -125,6 +125,7 @@ GNULIB_DUP2 = @GNULIB_DUP2@
 GNULIB_DUP3 = @GNULIB_DUP3@
 GNULIB_ENVIRON = @GNULIB_ENVIRON@
 GNULIB_EUIDACCESS = @GNULIB_EUIDACCESS@
+GNULIB_EXPLICIT_BZERO = @GNULIB_EXPLICIT_BZERO@
 GNULIB_FACCESSAT = @GNULIB_FACCESSAT@
 GNULIB_FCHDIR = @GNULIB_FCHDIR@
 GNULIB_FCHMODAT = @GNULIB_FCHMODAT@
@@ -390,6 +391,7 @@ HAVE_DPRINTF = @HAVE_DPRINTF@
 HAVE_DUP2 = @HAVE_DUP2@
 HAVE_DUP3 = @HAVE_DUP3@
 HAVE_EUIDACCESS = @HAVE_EUIDACCESS@
+HAVE_EXPLICIT_BZERO = @HAVE_EXPLICIT_BZERO@
 HAVE_FACCESSAT = @HAVE_FACCESSAT@
 HAVE_FCHDIR = @HAVE_FCHDIR@
 HAVE_FCHMODAT = @HAVE_FCHMODAT@
@@ -2411,6 +2413,7 @@ string.h: string.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
 	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
 	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
 	      -e 's|@''NEXT_STRING_H''@|$(NEXT_STRING_H)|g' \
+	      -e 's/@''GNULIB_EXPLICIT_BZERO''@/$(GNULIB_EXPLICIT_BZERO)/g' \
 	      -e 's/@''GNULIB_FFSL''@/$(GNULIB_FFSL)/g' \
 	      -e 's/@''GNULIB_FFSLL''@/$(GNULIB_FFSLL)/g' \
 	      -e 's/@''GNULIB_MBSLEN''@/$(GNULIB_MBSLEN)/g' \
@@ -2449,7 +2452,8 @@ string.h: string.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H
 	      -e 's/@''GNULIB_STRSIGNAL''@/$(GNULIB_STRSIGNAL)/g' \
 	      -e 's/@''GNULIB_STRVERSCMP''@/$(GNULIB_STRVERSCMP)/g' \
 	      < $(srcdir)/string.in.h | \
-	  sed -e 's|@''HAVE_FFSL''@|$(HAVE_FFSL)|g' \
+	  sed -e 's|@''HAVE_EXPLICIT_BZERO''@|$(HAVE_EXPLICIT_BZERO)|g' \
+	      -e 's|@''HAVE_FFSL''@|$(HAVE_FFSL)|g' \
 	      -e 's|@''HAVE_FFSLL''@|$(HAVE_FFSLL)|g' \
 	      -e 's|@''HAVE_MBSLEN''@|$(HAVE_MBSLEN)|g' \
 	      -e 's|@''HAVE_MEMCHR''@|$(HAVE_MEMCHR)|g' \

lib/string.in.h

@@ -74,6 +74,23 @@
 /* The definition of _GL_WARN_ON_USE is copied here.  */
 
 
+/* Clear a block of memory.  The compiler will not delete a call to
+   this function, even if the block is dead after the call.  */
+#if @GNULIB_EXPLICIT_BZERO@
+# if ! @HAVE_EXPLICIT_BZERO@
+_GL_FUNCDECL_SYS (explicit_bzero, void,
+                  (void *__dest, size_t __n) _GL_ARG_NONNULL ((1)));
+# endif
+_GL_CXXALIAS_SYS (explicit_bzero, void, (void *__dest, size_t __n));
+_GL_CXXALIASWARN (explicit_bzero);
+#elif defined GNULIB_POSIXCHECK
+# undef explicit_bzero
+# if HAVE_RAW_DECL_EXPLICIT_BZERO
+_GL_WARN_ON_USE (explicit_bzero, "explicit_bzero is unportable - "
+                 "use gnulib module explicit_bzero for portability");
+# endif
+#endif
+
 /* Find the index of the least-significant set bit.  */
 #if @GNULIB_FFSL@
 # if !@HAVE_FFSL@

m4/getdtablesize.m4

@@ -1,4 +1,4 @@
-# getdtablesize.m4 serial 6
+# getdtablesize.m4 serial 7
 dnl Copyright (C) 2008-2017 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -12,29 +12,43 @@ AC_DEFUN([gl_FUNC_GETDTABLESIZE],
   AC_CHECK_DECLS_ONCE([getdtablesize])
   if test $ac_cv_func_getdtablesize = yes &&
      test $ac_cv_have_decl_getdtablesize = yes; then
-    # Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft limit
-    # up to an unchangeable hard limit; all other platforms correctly
-    # require setrlimit before getdtablesize() can report a larger value.
     AC_CACHE_CHECK([whether getdtablesize works],
       [gl_cv_func_getdtablesize_works],
-      [AC_RUN_IFELSE([
-        AC_LANG_PROGRAM([[#include <unistd.h>]],
-          [int size = getdtablesize();
-           if (dup2 (0, getdtablesize()) != -1)
-             return 1;
-           if (size != getdtablesize())
-             return 2;
-          ])],
-        [gl_cv_func_getdtablesize_works=yes],
-        [gl_cv_func_getdtablesize_works=no],
-        [case "$host_os" in
-          cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows
-            gl_cv_func_getdtablesize_works="guessing no" ;;
-          *) gl_cv_func_getdtablesize_works="guessing yes" ;;
-         esac])
+      [dnl There are two concepts: the "maximum possible file descriptor value + 1"
+       dnl and the "maximum number of open file descriptors in a process".
+       dnl Per SUSv2 and POSIX, getdtablesize() should return the first one.
+       dnl On most platforms, the first and the second concept are the same.
+       dnl On OpenVMS, however, they are different and getdtablesize() returns
+       dnl the second one; thus the test below fails. But we don't care
+       dnl because there's no good way to write a replacement getdtablesize().
+       case "$host_os" in
+         vms*) gl_cv_func_getdtablesize_works="no (limitation)" ;;
+         *)
+           dnl Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft
+           dnl limit up to an unchangeable hard limit; all other platforms
+           dnl correctly require setrlimit before getdtablesize() can report
+           dnl a larger value.
+           AC_RUN_IFELSE([
+             AC_LANG_PROGRAM([[#include <unistd.h>]],
+               [int size = getdtablesize();
+                if (dup2 (0, getdtablesize()) != -1)
+                  return 1;
+                if (size != getdtablesize())
+                  return 2;
+               ])],
+             [gl_cv_func_getdtablesize_works=yes],
+             [gl_cv_func_getdtablesize_works=no],
+             [case "$host_os" in
+                cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows
+                  gl_cv_func_getdtablesize_works="guessing no" ;;
+                *) gl_cv_func_getdtablesize_works="guessing yes" ;;
+              esac
+             ])
+           ;;
+       esac
       ])
     case "$gl_cv_func_getdtablesize_works" in
-      *yes) ;;
+      *yes | "no (limitation)") ;;
       *) REPLACE_GETDTABLESIZE=1 ;;
     esac
   else

m4/string_h.m4

@@ -43,6 +43,7 @@ AC_DEFUN([gl_STRING_MODULE_INDICATOR],
 
 AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
 [
+  GNULIB_EXPLICIT_BZERO=0; AC_SUBST([GNULIB_EXPLICIT_BZERO])
   GNULIB_FFSL=0;        AC_SUBST([GNULIB_FFSL])
   GNULIB_FFSLL=0;       AC_SUBST([GNULIB_FFSLL])
   GNULIB_MEMCHR=0;      AC_SUBST([GNULIB_MEMCHR])
@@ -82,6 +83,7 @@ AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
   GNULIB_STRVERSCMP=0;  AC_SUBST([GNULIB_STRVERSCMP])
   HAVE_MBSLEN=0;        AC_SUBST([HAVE_MBSLEN])
   dnl Assume proper GNU behavior unless another module says otherwise.
+  HAVE_EXPLICIT_BZERO=1;        AC_SUBST([HAVE_EXPLICIT_BZERO])
   HAVE_FFSL=1;                  AC_SUBST([HAVE_FFSL])
   HAVE_FFSLL=1;                 AC_SUBST([HAVE_FFSLL])
   HAVE_MEMCHR=1;                AC_SUBST([HAVE_MEMCHR])