add a README warning devs from fracking around in extlib/

extlib/README

@@ -0,0 +1,58 @@
+DO NOT "FIX" CODE IN THIS DIRECTORY.
+
+ONLY UPSTREAM VERSIONS OF SOFTWARE GO IN THIS DIRECTORY.
+
+This directory is provided as a courtesy to our users who might be
+unable or unwilling to find and install libraries we depend on.
+
+If we "fix" software in this directory, we hamstring users who do the
+right thing and keep a single version of upstream libraries in a
+system-wide library. We introduce subtle and maddening bugs where
+our code is "accidentally" using the "wrong" library version. We may
+unwittingly interfere with other software that depends on the
+canonical release versions of those same libraries!
+
+Forking upstream software for trivial reasons makes us bad citizens in
+the Open Source community and adds unnecessary heartache for our
+users. Don't make us "that" project.
+
+FAQ:
+
+Q: What should we do when we find a bug in upstream software?
+
+A: First and foremost, REPORT THE BUG, and if possible send in a patch.
+
+   Watch for a release of the upstream software and integrate with it
+   when it's released.
+
+   In the meantime, work around the bug, if at all possible. Usually,
+   it's quite possible, if slightly harder or less efficient.
+
+Q: What if the bug can't be worked around?
+
+A: If the upstream developers have accepted a bug patch, it's
+   undesirable but acceptable to apply that patch to the library in
+   the extlib dir. Ideally, use a release version for upstream or a
+   version control system snapshot.
+
+   Note that this is a last resort.
+
+Q: What if upstream is unresponsive or won't accept a patch?
+
+A: Try again.
+
+Q: I tried again, and upstream is still unresponsive and nobody's
+   checked on my patch. Now what?
+
+A: If the upstream project is moribund and there's a way to adopt it,
+   propose having the StatusNet dev team adopt the project. Or, adopt
+   it yourself.
+
+Q: What if there's no upstream authority and it can't be adopted?
+
+A: Then we fork it. Make a new name and a new version. Include it in
+   lib/ instead of extlib/, and use the StatusNet_* prefix to change
+   the namespace to avoid collisions.
+
+   This is a last resort; consult with the rest of the dev group
+   before taking this radical step.