Update runtime files.
diff --git a/runtime/syntax/diff.vim b/runtime/syntax/diff.vim
index ac43d66..408556a 100644
--- a/runtime/syntax/diff.vim
+++ b/runtime/syntax/diff.vim
@@ -2,7 +2,7 @@
" Language: Diff (context or unified)
" Maintainer: Bram Moolenaar <Bram@vim.org>
" Translations by Jakson Alves de Aquino.
-" Last Change: 2020 Dec 07
+" Last Change: 2020 Dec 30
" Quit when a (custom) syntax file was already loaded
if exists("b:current_syntax")
@@ -348,11 +348,16 @@
syn match diffFile "^diff\>.*"
syn match diffFile "^Index: .*"
syn match diffFile "^==== .*"
-" Old style diff uses *** for old and --- for new.
-" Unified diff uses --- for old and +++ for new; names are wrong but it works.
-syn match diffOldFile "^+++ .*"
-syn match diffOldFile "^\*\*\* .*"
-syn match diffNewFile "^--- .*"
+
+if search('^@@ -\S\+ +\S\+ @@', 'nw', '', 100)
+ " unified
+ syn match diffOldFile "^--- .*"
+ syn match diffNewFile "^+++ .*"
+else
+ " context / old style
+ syn match diffOldFile "^\*\*\* .*"
+ syn match diffNewFile "^--- .*"
+endif
" Used by git
syn match diffIndexLine "^index \x\x\x\x.*"