math/py-numpy: Fix static library check that assumes atlas is installed
- Use BUILD_DEPENDS to check for the atlas static library at pre-build
time instead of checking if the file exists (False if atlas is not
- Replace IGNORE with a message to the user notifying them that
an atlas install WITH_STATIC is needed, and provide clues as possible
actions without being too prescriptive.
As discussed with eadler@, a correct resolution to "ports depending on other
ports with specific OPTIONS" is either an atlas slave port
(ie: atlas-static), or to modify atlas to install both shared and static
This change is a net gain on the existing broken behaviour, by fixing
the check, while retaining the user notification.
Reviewed by: jhibbits, eadler
Approved by: maintainer timeout (7+ months)