Switch bdw-gc to Github, add libatomic-ops.

Boehm's site won't feed the tarball to curl so it doesn't work with jhbuild

bdw-gc-7.2f adds libatomic_ops dependency.
Update libsoup to 2.46
Avoid defining _UINTXX_T on apple instead of just clang.
Patch wrong include order in old versions of gstreamer's gstdatetime.c

Swapping the positions of includes for glib-compat-private.h and
gst_private.h prevents getting the following error while building:

 error: use of undeclared identifier 'g_log_domain_gstreamer'

Note: This has been fixed upstream in gstreamer 1.2.1
Fix configure and compilation errors when building liboil

Use AC_CONFIG_HEADERS macro (instead of AM_CONFIG_HEADER) to allow
configuring, and add -fheinous-gnu-extensions to CFLAGS to avoid
getting a compilation error in amd64/wavelet.c when using Xcode 5.
Update vala to latest stable

This updates modulesets-stable to use Vala 0.26. The other module sets
were supposed to use the vala-bootstrap repository, but that is stuck
at 0.16 and is probably not going to be updated anymore, so use the
tarball of Vala 0.26 for the other module sets as well.
Several faad2 fixes

- CVS isn't shipped in OSX Mavericks, so build faad2 from tarball.
  (There hasn't been much activity at all on the CVS repository.)
- It needs a patch to change AM_CONFIG_HEADER into AC_CONFIG_HEADERS.
- Update the repository URLs in gtk-osx-gstreamer.modules.
Fix sutogen -> autogen typo
Update harfbuzz dependencies

Harfbuzz requires ragel; and apparently doesn't require freetype.