build: auto-generate syntax lists

Changes:

* Use the commands from contrib/vim/syntax/firejail.vim to create
  makefile targets to generate syntax lists in contrib/syntax/lists
* Add contrib/syntax/files/example.in as an example of how to generate
  syntax files
* Generate and add the syntax lists, to make it easier to spot if they
  are properly updated when a new command is added or if their recipes
  also need changes
* Add "syntax" and "contrib" makefile targets

Note: The generation commands are executed mostly silently to avoid
generating too much noise when also making other targets.

Note2: In some generation commands, a `$$` escape is used to pass `$` to
the shell, to avoid being interpreted by make as the start of a macro.

Note3: `@make_input@` is used in example.in to make it clear that the
file is generated (and that it is generated by make rather than
configure), similarly to how `@configure_input@` is used in configure
input files.  See also apparmor.vim:

    $ head -n 2 /usr/share/vim/vimfiles/syntax/apparmor.vim
    " generated from apparmor.vim.in by create-apparmor.vim.py
    " do not edit this file - edit apparmor.vim.in or create-apparmor.vim.py instead

Environment: apparmor 3.1.2-1 on Artix Linux.

Relates to #2679 #5502 #5577 #5612.

1 files changed, 1 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index 7333b1c8d..a6af8f67a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,7 @@ config.log
 config.mk
 config.sh
 config.status
+contrib/syntax/files/example
 firejail-*.tar.xz
 firejail-login.5
 firejail-profile.5