Building doc when `--disable-asciidoc' is broken on NetBSD. From 398012 in linus/makefile-var-exp: * doc/Makefile.am: Change $(VAR:MOD) to ${VAR:MOD} -- make(1) on NetBSD substitutes '$(:x)' to 'x' rather than the empty string. This bites us in doc/ when configured with `--disable-asciidoc'. Curly braces should work in all implementations of make(1) but this patch changes only the places where we use the VAR:MOD expansion. https://gitweb.torproject.org/linus/tor.git/shortlog/refs/heads/makefile-var-exp