Sparkle is an MIT-like-licensed framework used for Camino's auto-update
functionality. See http://sparkle.andymatuschak.org/ for more information about
Sparkle. The Sparkle framework is shipped inside Camino's bundle, and some glue
code is included in Camino itself.

This is a pull of af37928283042f985e6c7c6ce67869de74e39b52 from git://github.com/andymatuschak/Sparkle.git
with the following changes:
- Commented out used of [arch=<foo>] notation in ConfigCommon.xcconfig to allow building with our toolchain
- Commented out ARCHS in ConfigCommonRelease.xcconfig and replaced it with a version that doesn't include x86_64
- Changed GCC_GENERATE_DEBUGGING_SYMBOLS to YES (and set GCC_ENABLE_SYMBOL_SEPARATION to NO) in ConfigCommonRelease.xcconfig so that we get a dSYM bundle.
- Added null-checks to downloadFilename in SUAppcast.m to fix https://bugs.launchpad.net/sparkle/+bug/456514 and bug 560985.
