ENH: Added test cases to ensure the behavior of integer as it is.
There is a need to add test case which ensure and maintain the behaviour
of integer. As per pr #3567, which speed up integer scalar's operations
by avoiding the conversion of integer to NumPy Scalar.
Added test case for size of long based of os
added int test for error raises
DOC: hfft/ihfft description conflicts with itself

Says Hermite spectrum when it means signal
Removing test for OS choices on long conventions
ENH: Make the ndarray diagonal method return a view.

Also remove the test_diagonal_deprecation test and add test that
checks that a view is returned and that it is not writeable.

Closes #596.
Merge pull request #3645 from charris/enable-diagonal-as-view

ENH: Make the ndarray diagonal method return a view.
DOC: Add examples, copy some text from rfft functions to clarify inputs and outputs
DOC: add note clarifying why ifftshift is needed
Merge pull request #3592 from arinkverma/int_behaviour

ENH: Added test cases to ensure the behavior of integer as it is.
Small correction in the docstring of polyfit. As mentionned in Issue 3640, the notes were wrong in the order of the index for p.
FIX: wrong function types in ufunc_object.c

assign_reduce_identity_{zero,one} were treated as
PyArray_AssignReduceIdentityFunc, but that type has
an extra void* argument. Added the argument.
FIX: remove unused variables and add casts

Makes the build complete with fewer warnings.
MAINT: ignore some more generated C files.
Merge pull request #3653 from larsmans/c-fixes

FIX: call through wrong function pointer type + minor stuff
Merge pull request #3651 from MatthieuDartiailh/polyfit_doc

Small correction in the docstring of polyfit.
DOC: change "Hermite" to "Hermitian", "though" to "although"
DOC: Remove parentheses around axis
FIX: unchecked mallocs and Python operations

Rewrote _tmp_string_t handling in buffer.c to use the fact that
realloc(NULL, n) is equivalent to malloc(n). There are still some
unchecked cases in this file.

Also changed some arguments to const and removed casts on malloc
return values; malloc returns void*, which is converted to any
other pointer automatically. Casting the return value of malloc
is more likely to hide bugs than to fix anything.
MAINT: remove unused goto label and useless casts