maint: update gnulib to latest

* COPYING: Merge fom gnulib/doc/COPYINGv3.
* bootstrap: Merge from gnulib/build-aux/bootstrap.
* gnulib: Update, mainly to avoid the following warnings from GCC-8.1.1:
  cc1: warning: -Wabi won't warn about anything [-Wabi]
  cc1: note: -Wabi warns about differences from the most up-to-date ABI,\
       which is also used by default
  cc1: note: use e.g. -Wabi=11 to warn about changes from GCC 7

COPYING

@@ -1,12 +1,11 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
 
-		    GNU GENERAL PUBLIC LICENSE
-		       Version 3, 29 June 2007
-
- Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
 
-			    Preamble
+                            Preamble
 
   The GNU General Public License is a free, copyleft license for
 software and other kinds of works.
@@ -69,7 +68,7 @@ patents cannot be used to render the program non-free.
   The precise terms and conditions for copying, distribution and
 modification follow.
 
-		       TERMS AND CONDITIONS
+                       TERMS AND CONDITIONS
 
   0. Definitions.
 
@@ -77,7 +76,7 @@ modification follow.
 
   "Copyright" also means copyright-like laws that apply to other kinds of
 works, such as semiconductor masks.
- 
+
   "The Program" refers to any copyrightable work licensed under this
 License.  Each licensee is addressed as "you".  "Licensees" and
 "recipients" may be individuals or organizations.
@@ -510,7 +509,7 @@ actual knowledge that, but for the patent license, your conveying the
 covered work in a country, or your recipient's use of the covered work
 in a country, would infringe one or more identifiable patents in that
 country that you have reason to believe are valid.
-  
+
   If, pursuant to or in connection with a single transaction or
 arrangement, you convey, or propagate by procuring conveyance of, a
 covered work, and grant a patent license to some of the parties
@@ -619,9 +618,9 @@ an absolute waiver of all civil liability in connection with the
 Program, unless a warranty or assumption of liability accompanies a
 copy of the Program in return for a fee.
 
-		     END OF TERMS AND CONDITIONS
+                     END OF TERMS AND CONDITIONS
 
-	    How to Apply These Terms to Your New Programs
+            How to Apply These Terms to Your New Programs
 
   If you develop a new program, and you want it to be of the greatest
 possible use to the public, the best way to achieve this is to make it
@@ -672,5 +671,4 @@ into proprietary programs.  If your program is a subroutine library, you
 may consider it more useful to permit linking proprietary applications with
 the library.  If this is what you want to do, use the GNU Lesser General
 Public License instead of this License.  But first, please read
-<https://www.gnu.org/philosophy/why-not-lgpl.html>.
-
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

bootstrap

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Print a version string.
-scriptversion=2018-05-27.20; # UTC
+scriptversion=2018-07-25.07; # UTC
 
 # Bootstrap this package from checked-out sources.
 
@@ -142,6 +142,9 @@ die() { warn_ "$@"; exit 1; }
 
 # Configuration.
 
+# Name of the Makefile.am
+gnulib_mk=gnulib.mk
+
 # List of gnulib modules needed.
 gnulib_modules=
 
@@ -942,13 +945,13 @@ fi
 if $use_gnulib; then
   gnulib_tool_options="\
    --no-changelog\
-   --aux-dir $build_aux\
-   --doc-base $doc_base\
-   --lib $gnulib_name\
-   --m4-base $m4_base/\
-   --source-base $source_base/\
-   --tests-base $tests_base\
-   --local-dir $local_gl_dir\
+   --aux-dir=$build_aux\
+   --doc-base=$doc_base\
+   --lib=$gnulib_name\
+   --m4-base=$m4_base/\
+   --source-base=$source_base/\
+   --tests-base=$tests_base\
+   --local-dir=$local_gl_dir\
    $gnulib_tool_option_extras\
   "
   if test $use_libtool = 1; then

gnulib

@@ -1 +1 @@
-Subproject commit e64f847aeecaea35ca494b8db31807de167caf69
+Subproject commit c1599f2feb33dda51a23a3ac9e51a2e4bc98954d