BUG: fix scalar type memory leak

have an explicit tp_free that is different from PyObject_Free which is also the
tp_free of PyBaseObject so python does not COPYSLOT it, instead it takes the
next parent PyInt which has a different allocator.
Also added it for arrays just in case, currently not required as they don't
don't inherit from a python type.
BUG: IRR was returning nan instead of valid negative answer.

This change corrects the following two bugs in numpy.irr:

* When the solution was negative, numpy.irr returned nan instead of the
  correct solution because of the mask applied to the roots. Corrected
  by removing the mask that 0 < res < 1.
* When multiple roots were found, numpy.irr was returning an array of
  all roots rather than a single float. This bug was corrected by
  selecting the single root closest to zero (min(abs(root)).

With these corrections, numpy.irr returns the same result as the
corresponding spreadsheet function in LibreOffice Calc for all test
cases (additional test cases were added to cover cases with multiple
positive and negative roots)
Merge pull request #4248 from juliantaylor/scalar-memleak

BUG: fix scalar type memory leak
Detect vendor versions of GNU Compilers

Cray and other HPC vendors provide patched versions of the GNU compilers
with modified version strings.  Use re.search instead of re.match in the
version detection scripts to account for modified version strings.

Ref: https://github.com/numpy/numpy/issues/4259
ENH: remove insecure mktemp use

mktemp only returns a filename, a malicous user could replace it before
it gets used.
Merge pull request #4262 from juliantaylor/mktemp-remove

remove insecure mktemp usage
ENH: Attempt to rewrite the index parsing.

Some optimizations still missing.
WIP: Speed improvements by using EXTERNAL_LOOP
WIP,TST: Fix tests to match new behaviour
WIP: use fast_take and fix Deprecations
WIP,TST: Small fixes for the tests
WIP: bug fixes and field oder access change
WIP,TST: Fixup python3 tests
WIP: fix field order; And MapIterNext iteration end
WIP,TST,DOC: tiny fix

maybe triggers Travis too...
WIP: Move Ellipsis setting check and clear warnings
WIP: Restore binary compatibility of MapIterObject (hopefully)
WIP,ENH: Already allow boolean scalars for 0-d arrays

Since indexing into a 0-d array with an integer is impossible,
we can disable any conversion/interpretation is integer code
to special case the 0-d array for now and fix this annoying
issue...
WIP,BUG: Fix outer iteration bug.
Attempt to start optimizing setmap