Ship the asciidoc-helper file in our tarballs

Otherwise, the build process breaks when one of the .1.txt gets
a new mtime. Suggested by weasel.

ChangeLog

@@ -23,6 +23,9 @@ Changes in version 0.2.2.10-alpha - 2010-??-??
       fixes bug 1255.
     - Disallow values larger than INT32_MAX for PerConnBWRate|Burst
       config option. Bugfix on 0.2.2.7-alpha.
+    - Ship the asciidoc-helper file in the tarball, so that people can
+      build from source if they want to, and touching the .1.txt files
+      doesn't break the build. Bugfix on 0.2.2.9-alpha.
 
   o Code simplifications and refactoring:
     - Fix some urls in the exit notice file and make it XHTML1.1 strict

doc/Makefile.am

@@ -19,7 +19,7 @@ html_in = $(asciidoc_files:=.html.in)
 
 man_in = $(asciidoc_files:=.1.in)
 
-EXTRA_DIST = HACKING                                         \
+EXTRA_DIST = HACKING asciidoc-helper.sh                      \
              $(html_in) $(man_in) $(asciidoc_files:=.1.txt)  \
              tor-osx-dmg-creation.txt tor-rpm-creation.txt   \
              tor-win32-mingw-creation.txt