patch 8.2.2086: libvterm tests are only run on Linux

Problem:    Libvterm tests are only run on Linux.
Solution:   Use static libraries. (Ozaki Kiichi, closes #7419)
diff --git a/.travis.yml b/.travis.yml
index d3bb301..b89f276 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -240,8 +240,6 @@
       env:
         - *linux-huge
         - *coverage
-        # Clang cannot compile test_libvterm with "--coverage" flag.
-        - TEST=scripttests
       after_success: *eval-coverage
     - <<: *linux
       name: huge+coverage/gcc
diff --git a/src/Makefile b/src/Makefile
index 05c32a2..c30af8b 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2293,11 +2293,10 @@
 	$(VALGRIND) ./$(MESSAGE_TEST_TARGET) || exit 1; echo $* passed;
 
 # Run the libvterm tests.
-# This currently doesn't work on Mac, only run on Linux for now.
+# This works only on GNU make, not on BSD make.
 test_libvterm:
-	@if test `uname` = "Linux"; then \
-		cd libvterm; $(MAKE) -f Makefile test \
-			CC="$(CC)" CFLAGS="$(CFLAGS)" LDFLAGS="$(LDFLAGS)"; \
+	@if $(MAKE) --version 2>/dev/null | grep -qs "GNU Make"; then \
+		cd libvterm; $(MAKE) -f Makefile test CC="$(CC)" CFLAGS="$(CFLAGS)" LDFLAGS="$(LDFLAGS)"; \
 	fi
 
 # Run individual OLD style test.
diff --git a/src/libvterm/Makefile b/src/libvterm/Makefile
index 852c97f..be01dd0 100644
--- a/src/libvterm/Makefile
+++ b/src/libvterm/Makefile
@@ -78,7 +78,7 @@
 	$(LIBTOOL) --mode=compile --tag=CC $(CC) $(CFLAGS) -o $@ -c $<
 
 t/harness: t/harness.lo $(LIBRARY)
-	$(LIBTOOL) --mode=link --tag=CC $(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+	$(LIBTOOL) --mode=link --tag=CC $(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS) -static
 
 .PHONY: test
 test: $(LIBRARY) t/harness
diff --git a/src/libvterm/t/run-test.pl b/src/libvterm/t/run-test.pl
index 96f47fb..82abb29 100644
--- a/src/libvterm/t/run-test.pl
+++ b/src/libvterm/t/run-test.pl
@@ -8,7 +8,7 @@
 use POSIX qw( WIFEXITED WEXITSTATUS WIFSIGNALED WTERMSIG );
 
 my $VALGRIND = 0;
-my $EXECUTABLE = "t/.libs/harness";
+my $EXECUTABLE = "t/harness";
 GetOptions(
    'valgrind|v+' => \$VALGRIND,
    'executable|e=s' => \$EXECUTABLE,
@@ -17,7 +17,6 @@
 
 my ( $hin, $hout, $hpid );
 {
-   local $ENV{LD_LIBRARY_PATH} = ".libs";
    my @command = $EXECUTABLE;
    unshift @command, "valgrind", "--tool=memcheck", "--leak-check=yes", "--num-callers=25", "--log-file=valgrind.out", "--error-exitcode=126" if $VALGRIND;
 
diff --git a/src/version.c b/src/version.c
index 096698b..eb5a8e2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2086,
+/**/
     2085,
 /**/
     2084,