Remove hard-coded ~/lib/python/ in py_usStandard Makefile

[martin-rdz]

Issue

Modifications of PYINSTDIR are not propagated down to the sub-make of py_usStandard.

Fix

Use the export of make variables (https://www.gnu.org/savannah-checkouts/gnu/make/manual/html_node/Variables_002fRecursion.html)

Change in pamtra makefile

PYINSTDIR := ~/lib/python/
export PYINSTDIR

and in tools/py_usStandard/Makefile:

install: usStandardAtmosphere.so
     cp *.py $(PYINSTDIR)
     cp *.so $(PYINSTDIR)

[DaveOri]

Hi Martin, I was working on a more pressing issue #52 whose current solution in branch mesonpy would automatically solve also this issue.
Cheers,
Davide

[maahn]

Fixed because we finally got rid of the py_usStandard submodule aa8fa38