Add syntax files from upstream vim repository

syntax/fvwm2m4.vim

@@ -0,0 +1,36 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'vim') == -1
+  
+" Vim syntax file
+" Language: FvwmM4 preprocessed Fvwm2 configuration files
+" Maintainer: David Ne\v{c}as (Yeti) <yeti@physics.muni.cz>
+" Last Change: 2002-06-02
+" URI: http://physics.muni.cz/~yeti/download/syntax/fvwmm4.vim
+
+" Setup
+" quit when a syntax file was already loaded
+if exists('b:current_syntax')
+  finish
+endif
+
+" Let included files know they are included
+if !exists('main_syntax')
+  let main_syntax = 'fvwm2m4'
+endif
+
+" Include M4 syntax
+runtime! syntax/m4.vim
+unlet b:current_syntax
+
+" Include Fvwm2 syntax (Fvwm1 doesn't have M4 preprocessor)
+runtime! syntax/fvwm.vim
+unlet b:current_syntax
+
+" That's all!
+let b:current_syntax = 'fvwm2m4'
+
+if main_syntax == 'fvwm2m4'
+  unlet main_syntax
+endif
+
+
+endif