Release GNU make 3.81.

Update NEWS docs.
Enhance the manual to use automake version.texi, and use the canonical
FSF copyright features and statement.
Some $(realpath ...) tests won't work on Windows; leave them out
The jobserver filedescriptor test might fail if some FDs are reserved,
so for now comment out that check.

tests/scripts/features/parallelism

@@ -128,31 +128,37 @@ mod_a.o mod_b.o:
 
 # Make sure that all jobserver FDs are closed if we need to re-exec the
 # master copy.
+#
+# First, find the "default" file descriptors we normally use
+# Then make sure they're still used.
+#
+# Right now we don't have a way to run a makefile and capture the output
+# without checking it, so we can't really write this test.
 
-run_make_test('
-submake: ; @$(MAKE) --no-print-directory -f #MAKEFILE# fdprint 5>output
+# run_make_test('
+# submake: ; @$(MAKE) --no-print-directory -f #MAKEFILE# fdprint 5>output
 
-dependfile: ; @echo FOO=bar > $@
+# dependfile: ; @echo FOO=bar > $@
 
-INCL := true
+# INCL := true
 
-FOO=foo
-ifeq ($(INCL),true)
--include dependfile
-endif
+# FOO=foo
+# ifeq ($(INCL),true)
+# -include dependfile
+# endif
 
-fdprint: ; @echo hi >&5 && echo "$(FOO)"
+# fdprint: ; @echo $(filter --jobserver%,$(MAKEFLAGS))
 
-recurse: ; @$(MAKE) --no-print-directory -f #MAKEFILE# submake INCL=true',
-              '-j2',
-              'bar');
+# recurse: ; @$(MAKE) --no-print-directory -f #MAKEFILE# submake INCL=true',
+#               '-j2 INCL=false fdprint',
+#               'bar');
 
-unlink('dependfile', 'output');
+# unlink('dependfile', 'output');
 
 
-# Do it again, this time where the include is done by the non-master make.
-run_make_test(undef, '-j2 recurse INCL=false', 'bar');
+# # Do it again, this time where the include is done by the non-master make.
+# run_make_test(undef, '-j2 recurse INCL=false', 'bar');
 
-unlink('dependfile', 'output');
+# unlink('dependfile', 'output');
 
 1;

tests/scripts/functions/realpath

@@ -20,18 +20,10 @@ ifneq ($(realpath /),/)
   $(error )
 endif
 
-ifneq ($(realpath ///),/)
-  $(error )
-endif
-
 ifneq ($(realpath /.),/)
   $(error )
 endif
 
-ifneq ($(realpath ///.),/)
-  $(error )
-endif
-
 ifneq ($(realpath /./),/)
   $(error )
 endif
@@ -44,10 +36,6 @@ ifneq ($(realpath /..),/)
   $(error )
 endif
 
-ifneq ($(realpath ///..),/)
-  $(error )
-endif
-
 ifneq ($(realpath /../),/)
   $(error )
 endif
@@ -63,8 +51,31 @@ endif
 .PHONY: all
 all: ; @:
 ',
-'',
-'');
+              '',
+              '');
+
+# On Windows platforms, "//" means something special.  So, don't do these
+# tests there.
+
+if ($port_type ne 'W32') {
+  run_make_test('
+ifneq ($(realpath ///),/)
+  $(error )
+endif
+
+ifneq ($(realpath ///.),/)
+  $(error )
+endif
+
+ifneq ($(realpath ///..),/)
+  $(error )
+endif
+
+.PHONY: all
+all: ; @:',
+                '',
+                '');
+}
 
 
 # This tells the test driver that the perl test script executed properly.