Update from Gnulib.

This incorporates:
2020-06-28 getrandom: do not depend on ‘open’ on mingw
2020-06-28 getrandom: fix compilation errors on older versions of mingw
* build-aux/config.sub, lib/getrandom.c, m4/getrandom.m4:
Copy from Gnulib
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.

lib/getrandom.c

@@ -29,7 +29,16 @@
 #if defined _WIN32 && ! defined __CYGWIN__
 # define WIN32_LEAN_AND_MEAN
 # include <windows.h>
-# include <bcrypt.h>
+# if HAVE_BCRYPT_H
+#  include <bcrypt.h>
+# else
+#  include <ntdef.h> /* NTSTATUS */
+typedef void * BCRYPT_ALG_HANDLE;
+#  define BCRYPT_USE_SYSTEM_PREFERRED_RNG 0x00000002
+#  if HAVE_LIB_BCRYPT
+extern NTSTATUS WINAPI BCryptGenRandom (BCRYPT_ALG_HANDLE, UCHAR *, ULONG, ULONG);
+#  endif
+# endif
 # if !HAVE_LIB_BCRYPT
 #  include <wincrypt.h>
 #  ifndef CRYPT_VERIFY_CONTEXT

lib/gnulib.mk.in

@@ -109,6 +109,7 @@
 #  futimens \
 #  getloadavg \
 #  getopt-gnu \
+#  getrandom \
 #  gettime \
 #  gettimeofday \
 #  gitlog-to-changelog \
@@ -1095,6 +1096,7 @@ gl_GNULIB_ENABLED_getdtablesize = @gl_GNULIB_ENABLED_getdtablesize@
 gl_GNULIB_ENABLED_getgroups = @gl_GNULIB_ENABLED_getgroups@
 gl_GNULIB_ENABLED_lchmod = @gl_GNULIB_ENABLED_lchmod@
 gl_GNULIB_ENABLED_malloca = @gl_GNULIB_ENABLED_malloca@
+gl_GNULIB_ENABLED_open = @gl_GNULIB_ENABLED_open@
 gl_GNULIB_ENABLED_strtoll = @gl_GNULIB_ENABLED_strtoll@
 gl_GNULIB_ENABLED_utimens = @gl_GNULIB_ENABLED_utimens@
 gl_LIBOBJS = @gl_LIBOBJS@
@@ -2168,7 +2170,9 @@ endif
 ## begin gnulib module open
 ifeq (,$(OMIT_GNULIB_MODULE_open))
 
+ifneq (,$(gl_GNULIB_ENABLED_open))
 
+endif
 EXTRA_DIST += open.c
 
 EXTRA_libgnu_a_SOURCES += open.c

m4/getrandom.m4

@@ -1,4 +1,4 @@
-# getrandom.m4 serial 5
+# getrandom.m4 serial 6
 dnl Copyright 2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -36,6 +36,7 @@ AC_DEFUN([gl_FUNC_GETRANDOM],
 
   case "$host_os" in
     mingw*)
+      AC_CHECK_HEADERS([bcrypt.h])
       AC_CACHE_CHECK([whether the bcrypt library is guaranteed to be present],
         [gl_cv_lib_assume_bcrypt],
         [AC_COMPILE_IFELSE(

m4/gnulib-comp.m4

@@ -308,6 +308,7 @@ AC_DEFUN([gl_INIT],
     AC_LIBOBJ([futimens])
   fi
   gl_SYS_STAT_MODULE_INDICATOR([futimens])
+  AC_REQUIRE([AC_CANONICAL_HOST])
   gl_GETLOADAVG
   if test $HAVE_GETLOADAVG = 0; then
     AC_LIBOBJ([getloadavg])
@@ -327,6 +328,7 @@ AC_DEFUN([gl_INIT],
   fi
   AC_SUBST([GNULIB_GL_UNISTD_H_GETOPT])
   gl_UNISTD_MODULE_INDICATOR([getopt-posix])
+  AC_REQUIRE([AC_CANONICAL_HOST])
   gl_FUNC_GETRANDOM
   if test $HAVE_GETRANDOM = 0 || test $REPLACE_GETRANDOM = 1; then
     AC_LIBOBJ([getrandom])
@@ -383,12 +385,6 @@ AC_DEFUN([gl_INIT],
   gl_TIME_MODULE_INDICATOR([mktime])
   gl_MULTIARCH
   gl_FUNC_GNU_STRFTIME
-  gl_FUNC_OPEN
-  if test $REPLACE_OPEN = 1; then
-    AC_LIBOBJ([open])
-    gl_PREREQ_OPEN
-  fi
-  gl_FCNTL_MODULE_INDICATOR([open])
   gl_PATHMAX
   gl_FUNC_PIPE2
   gl_UNISTD_MODULE_INDICATOR([pipe2])
@@ -509,6 +505,7 @@ AC_DEFUN([gl_INIT],
   gl_gnulib_enabled_2049e887c7e5308faad27b3f894bb8c9=false
   gl_gnulib_enabled_malloca=false
   gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31=false
+  gl_gnulib_enabled_open=false
   gl_gnulib_enabled_03e0aaad4cb89ca757653bd367a6ccb7=false
   gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c=false
   gl_gnulib_enabled_strtoll=false
@@ -517,7 +514,11 @@ AC_DEFUN([gl_INIT],
   func_gl_gnulib_m4code_260941c0e5dc67ec9e87d1fb321c300b ()
   {
     if ! $gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b; then
+      AC_REQUIRE([AC_CANONICAL_HOST])
       gl_gnulib_enabled_260941c0e5dc67ec9e87d1fb321c300b=true
+      if case $host_os in mingw*) false;; *) :;; esac; then
+        func_gl_gnulib_m4code_open
+      fi
     fi
   }
   func_gl_gnulib_m4code_cloexec ()
@@ -644,6 +645,21 @@ AC_DEFUN([gl_INIT],
       gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31=true
     fi
   }
+  func_gl_gnulib_m4code_open ()
+  {
+    if ! $gl_gnulib_enabled_open; then
+      gl_FUNC_OPEN
+      if test $REPLACE_OPEN = 1; then
+        AC_LIBOBJ([open])
+        gl_PREREQ_OPEN
+      fi
+      gl_FCNTL_MODULE_INDICATOR([open])
+      gl_gnulib_enabled_open=true
+      if test $REPLACE_OPEN = 1; then
+        func_gl_gnulib_m4code_cloexec
+      fi
+    fi
+  }
   func_gl_gnulib_m4code_03e0aaad4cb89ca757653bd367a6ccb7 ()
   {
     if ! $gl_gnulib_enabled_03e0aaad4cb89ca757653bd367a6ccb7; then
@@ -720,15 +736,18 @@ AC_DEFUN([gl_INIT],
   if test $HAVE_FUTIMENS = 0 || test $REPLACE_FUTIMENS = 1; then
     func_gl_gnulib_m4code_utimens
   fi
+  if case $host_os in mingw*) false;; *) test $HAVE_GETLOADAVG = 0;; esac; then
+    func_gl_gnulib_m4code_open
+  fi
   if test $REPLACE_GETOPT = 1; then
     func_gl_gnulib_m4code_be453cec5eecf5731a274f2de7f2db36
   fi
+  if case $host_os in mingw*) false;; *) test $HAVE_GETRANDOM = 0 || test $REPLACE_GETRANDOM = 1;; esac; then
+    func_gl_gnulib_m4code_open
+  fi
   if test $NEED_LOCALTIME_BUFFER = 1; then
     func_gl_gnulib_m4code_2049e887c7e5308faad27b3f894bb8c9
   fi
-  if test $REPLACE_OPEN = 1; then
-    func_gl_gnulib_m4code_cloexec
-  fi
   if test $HAVE_READLINKAT = 0; then
     func_gl_gnulib_m4code_260941c0e5dc67ec9e87d1fb321c300b
   fi
@@ -763,6 +782,7 @@ AC_DEFUN([gl_INIT],
   AM_CONDITIONAL([gl_GNULIB_ENABLED_2049e887c7e5308faad27b3f894bb8c9], [$gl_gnulib_enabled_2049e887c7e5308faad27b3f894bb8c9])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_malloca], [$gl_gnulib_enabled_malloca])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_5264294aa0a5557541b53c8c741f7f31], [$gl_gnulib_enabled_5264294aa0a5557541b53c8c741f7f31])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_open], [$gl_gnulib_enabled_open])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_03e0aaad4cb89ca757653bd367a6ccb7], [$gl_gnulib_enabled_03e0aaad4cb89ca757653bd367a6ccb7])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_6099e9737f757db36c47fa9d9f02e88c], [$gl_gnulib_enabled_6099e9737f757db36c47fa9d9f02e88c])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_strtoll], [$gl_gnulib_enabled_strtoll])