Some major updates including heuristics

- Allow to define heuristics in heuristics.yaml
- Migrate all filetypes from vim beginning with "a"
- Remove enhanced cpp syntax (it was too slow to load)
- Use setf instead of set ft for setting filetype (faster)
- Override native hauristics with au!
- Add globbing of files for packages
- Replace predefined dirs with extra_dirs and ignored_dirs
- Allow to define proper order of packages with topological sort
- Fix powershell detection
- Lint and fix many packages.yaml issues
- etc etd

syntax/m4.vim

@@ -0,0 +1,64 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'm4') == -1
+
+" Vim syntax file
+" Language:		M4
+" Maintainer:	Claudio Fleiner (claudio@fleiner.com)
+" URL:			http://www.fleiner.com/vim/syntax/m4.vim
+" Last Change:	2005 Jan 15
+
+" This file will highlight user function calls if they use only
+" capital letters and have at least one argument (i.e. the '('
+" must be there). Let me know if this is a problem.
+
+" quit when a syntax file was already loaded
+if !exists("main_syntax")
+  if exists("b:current_syntax")
+	finish
+  endif
+  " we define it here so that included files can test for it
+  let main_syntax='m4'
+endif
+
+" define the m4 syntax
+syn match  m4Variable contained "\$\d\+"
+syn match  m4Special  contained "$[@*#]"
+syn match  m4Comment  "\<\(m4_\)\=dnl\>.*" contains=SpellErrors
+syn match  m4Constants "\<\(m4_\)\=__file__"
+syn match  m4Constants "\<\(m4_\)\=__line__"
+syn keyword m4Constants divnum sysval m4_divnum m4_sysval
+syn region m4Paren    matchgroup=m4Delimiter start="(" end=")" contained contains=@m4Top
+syn region m4Command  matchgroup=m4Function  start="\<\(m4_\)\=\(define\|defn\|pushdef\)(" end=")" contains=@m4Top
+syn region m4Command  matchgroup=m4Preproc   start="\<\(m4_\)\=\(include\|sinclude\)("he=e-1 end=")" contains=@m4Top
+syn region m4Command  matchgroup=m4Statement start="\<\(m4_\)\=\(syscmd\|esyscmd\|ifdef\|ifelse\|indir\|builtin\|shift\|errprint\|m4exit\|changecom\|changequote\|changeword\|m4wrap\|debugfile\|divert\|undivert\)("he=e-1 end=")" contains=@m4Top
+syn region m4Command  matchgroup=m4builtin start="\<\(m4_\)\=\(len\|index\|regexp\|substr\|translit\|patsubst\|format\|incr\|decr\|eval\|maketemp\)("he=e-1 end=")" contains=@m4Top
+syn keyword m4Statement divert undivert
+syn region m4Command  matchgroup=m4Type      start="\<\(m4_\)\=\(undefine\|popdef\)("he=e-1 end=")" contains=@m4Top
+syn region m4Function matchgroup=m4Type      start="\<[_A-Z][_A-Z0-9]*("he=e-1 end=")" contains=@m4Top
+syn region m4String   start="`" end="'" contained contains=@m4Top,@m4StringContents,SpellErrors
+syn cluster m4Top     contains=m4Comment,m4Constants,m4Special,m4Variable,m4String,m4Paren,m4Command,m4Statement,m4Function
+
+" Define the default highlighting.
+" Only when an item doesn't have highlighting yet
+hi def link m4Delimiter Delimiter
+hi def link m4Comment   Comment
+hi def link m4Function  Function
+hi def link m4Keyword   Keyword
+hi def link m4Special   Special
+hi def link m4String    String
+hi def link m4Statement Statement
+hi def link m4Preproc   PreProc
+hi def link m4Type      Type
+hi def link m4Special   Special
+hi def link m4Variable  Special
+hi def link m4Constants Constant
+hi def link m4Builtin   Statement
+
+let b:current_syntax = "m4"
+
+if main_syntax == 'm4'
+  unlet main_syntax
+endif
+
+" vim: ts=4
+
+endif