compile fix

Without this I get

	$ make
	aclocal --acdir=./m4 --output=aclocal.m4
	aclocal: error: unrecognized option '--acdir=./m4'.
	aclocal: Try '/usr/bin/aclocal --help' for more information.
	make: *** [aclocal.m4] Error 1

on my Fedora 20 machine.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Makefile

@@ -75,7 +75,7 @@ $(CONFIGURE): aclocal.m4
 	touch .census
 
 aclocal.m4::
-	aclocal --acdir=$(TOPDIR)/m4 --output=$@
+	aclocal --output=$@
 
 # we don't have any docs to install just now ...
 #