python-numpy: Ensure `_npy_scaled_cexp{, f, l}` is defined when needed

python-numpy: Ensure `_npy_scaled_cexp{, f, l}` is defined when needed

With update of Numpy to the latest version we've got one change which
breaks Numpy compilcation in some cases.

This change back-ports upstream fix from:
https://github.com/numpy/numpy/pull/9740

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Rahul Bedarkar <rahulbedarkar89@gmail.com>
Cc: Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>