meta-python: outrageously long cython shebang with pyro

["S. Lockwood-Childs" <sjl@vctlabs.com>]

The recipe-specific sysroots in pyro are a wonderful thing for uncovering 
missing dependencies, but they also make it easier than ever to break
the cython scripts by exceeding the measly 128-byte limit on shebang lines. 

The cython recipe builds fine -- this is runtime breakage from recipes that
depend on cython. This was always a danger when using lengthy toplevel
directory names (e.g. as tends to happen in jenkins auto-builds), but
now I managed to get the dreaded "bad interpreter: No such file or directory"
failure from cython despite a not-ridiculously-long toplevel path:

#!/var/data/sjl/poky/build/tmp/work/armv7a-neon-oe-linux-gnueabi/libplist/git-r0/recipe-sysroot-native/usr/bin/python-native/python

Does anybody know of a recommended strategy for solving the shebang problem,
now that it has been exacerbated by the sysroot move? I'll be happy to submit a
corresponding cython patch if so.