patch 7.4.2223

Problem:    Buffer overflow when using latin1 character with feedkeys().
Solution:   Check for an illegal character.  Add a test.

src/testdir/test_source_utf8.vim

@@ -0,0 +1,33 @@
+" Test the :source! command
+if !has('multi_byte')
+  finish
+endif
+
+func Test_source_utf8()
+  " check that sourcing a script with 0x80 as second byte works
+  new
+  call setline(1, [':%s/àx/--à1234--/g', ':%s/Àx/--À1234--/g'])
+  write! Xscript
+  bwipe!
+  new
+  call setline(1, [' àx ', ' Àx '])
+  source! Xscript | echo
+  call assert_equal(' --à1234-- ', getline(1))
+  call assert_equal(' --À1234-- ', getline(2))
+  bwipe!
+  call delete('Xscript')
+endfunc
+
+func Test_source_latin()
+  " check that sourcing a latin1 script with a 0xc0 byte works
+  new
+  call setline(1, ["call feedkeys('r')", "call feedkeys('\xc0', 'xt')"])
+  write! Xscript
+  bwipe!
+  new
+  call setline(1, ['xxx'])
+  source Xscript
+  call assert_equal("\u00c0xx", getline(1))
+  bwipe!
+  call delete('Xscript')
+endfunc