patch 8.1.0978: blob not tested with Perl

Problem:    Blob not tested with Perl.
Solution:   Add more test coverage.  Fixes a crash. (Dominique Pelle,
            closes #4037)

src/if_perl.xs

@@ -1570,7 +1570,7 @@ Blob(SV* sv)
     newsv = newSVpv("0z", 2);
     for (i = 0; i < len; i++)
     {
-	sprintf(buf, "%02X", s[i]);
+	sprintf(buf, "%02X", (unsigned char)(s[i]));
 	sv_catpvn(newsv, buf, 2);
     }
     RETVAL = newsv;

src/testdir/test_perl.vim

@@ -29,6 +29,13 @@ EOF
   call assert_equal('abc/def/', getline('$'))
 endfunc
 
+funct Test_VIM_Blob()
+  call assert_equal('0z',         perleval('VIM::Blob("")'))
+  call assert_equal('0z31326162', perleval('VIM::Blob("12ab")'))
+  call assert_equal('0z00010203', perleval('VIM::Blob("\x00\x01\x02\x03")'))
+  call assert_equal('0z8081FEFF', perleval('VIM::Blob("\x80\x81\xfe\xff")'))
+endfunc
+
 func Test_buffer_Delete()
   new
   call setline(1, ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'])

src/version.c

@@ -779,6 +779,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    978,
 /**/
     977,
 /**/