BUG: Fix generalized ufunc so repeating labels in one input/output is ok
BUG: Missed case of broadcasting onto core dimensions in gufunc
BUG: Make sure the nditer doesn't complain when 0 broadcast dims
TST: Add test for gufunc scalar case
BUG: Fix bug in gufunc scalar case
TST: Test for a generalized ufunc bug, for zero-sized inputs
BUG: Fix for generalized ufunc zero-sized input case
compile fix on linux/mac
BUG: Choose a more unique PY_ARRAY_UNIQUE_SYMBOL in f2py.

In a few exceptional cases where symbols are shared between different
Python modules the use of `PyArray_API` in f2py (fortranobject.h)
conflicts with the regular use of the same symbol in the multiarray
module. Generally the symptom of this conflicting use is a segfault
when importing a f2py'ed module. This occurs because the module init
code somehow overwrites the first element of `PyArray_API` with the
location of `PyArray_API`, causing a crash when
`PyArray_GetNDArrayCVersion` is called.

Closes gh-2521.
DOC: Remove documentation of non-existing advanced iter NA flags.
Merge pull request #3106 from seberg/remove-maskNA-nditer-doc

DOC: Remove documentation of non-existing advanced iter NA flags.
Merge pull request #3014 from bfroehle/f2py_unque_symbol

BUG: Choose a more unique PY_ARRAY_UNIQUE_SYMBOL in f2py.
Merge pull request #2953 from ContinuumIO/gufunc-fix

generalized ufunc signature problem fix