patch 8.1.1100: tag file without trailing newline no longer works

Problem:    Tag file without trailing newline no longer works. (Marco Hinz)
Solution:   Don't expect a newline at the end of the file. (closes #4200)

src/tag.c

@@ -1943,14 +1943,16 @@ line_read_in:
 	    }
 
 parse_line:
-	    if (vim_strchr(lbuf, NL) == NULL
+	    // When the line is too long the NUL will not be in the
+	    // last-but-one byte (see vim_fgets()).
+	    // Has been reported for Mozilla JS with extremely long names.
+	    // In that case we can't parse it and we ignore the line.
+	    if (lbuf[LSIZE - 2] != NUL
 #ifdef FEAT_CSCOPE
 					     && !use_cscope
 #endif
 					     )
 	    {
-		// Truncated line, ignore it.  Has been reported for
-		// Mozilla JS with extremely long names.
 		if (p_verbose >= 5)
 		{
 		    verbose_enter();

src/testdir/test_taglist.vim

@@ -98,3 +98,16 @@ func Test_tagfiles()
   call delete('Xtags2')
   bd
 endfunc
+
+" For historical reasons we support a tags file where the last line is missing
+" the newline.
+func Test_tagsfile_without_trailing_newline()
+  call writefile(["Foo\tfoo\t1"], 'Xtags', 'b')
+  set tags=Xtags
+
+  let tl = taglist('.*')
+  call assert_equal(1, len(tl))
+  call assert_equal('Foo', tl[0].name)
+
+  call delete('Xtags')
+endfunc

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1100,
 /**/
     1099,
 /**/