Expanding the autoconf syntax a little, by handling .m4 files too, adding the

"elif" keyword, handling dnl comments better, and marking trailing whitespace.
Patch by Mike Frysinger.


git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@5506 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

ChangeLog

+2015-12-23  Mike Frysinger  <vapier@gentoo.org>
+	* doc/syntax/autoconf.nanorc: Handle .m4 files too, add the "elif"
+	keyword, handle dnl comments better, and mark trailing whitespace.
+
 2015-12-23  Christian Weisgerber  <naddy@mips.inka.de>
 	* configure.ac: AC_CHECK_HEADERS_ONCE() is very special and cannot be
 	conditionalized.  Use plain AC_CHECK_HEADERS() instead, to not check

doc/syntax/autoconf.nanorc

 ## Here is an example for Autoconf.
 
-syntax "autoconf" "\.ac$"
+syntax "autoconf" "\.(ac|m4)$"
 
 # Keywords:
-color yellow "\<(if|test|then|else|fi|for|in|do|done)\>"
+color yellow "\<(if|test|then|elif|else|fi|for|in|do|done)\>"
 color yellow "(=|!=|&&|\|\|)"
 
 # Macros:
@@ -25,4 +25,7 @@ color black "^\*\*\*.*"
 color magenta "\[|\]|\(|\)"
 
 # Comments:
-color blue "^[[:blank:]]*#.*"  "^dnl.*"
+color blue "^[[:blank:]]*#.*"  "\<dnl.*"
+
+# Trailing whitespace:
+color ,green "[[:space:]]+$"