For reasons that are a bit beyond me, `--host` and `PLATFORM_TRIPLET`
seem to be independent, in particular we've had an empty
`PLATFORM_TRIPLET`. This is unfortunate because `PLATFORM_TRIPLET`
is used to generate the SOABI config variable which in turn is used
to decide whether a .so file is a good match for loading. We'd like
for linux Pythons not to try to import emscripten .so files (it
raises `ImportError: some_file.so: invalid ELF header`). Similarly,
we'd like to avoid attempting to load linux .so files in wasm. These
platform tags are our friends.

Anyways, this PR sets `PLATFORM_TRIPLET` and ensures that .so files
built by pywasmcross are tagged with our SOABI tag.

I moved the .so file renaming from pywasmcross to buildpkg just
before running the post script. That is a better place to put it in
case the package wants to look at the .so file after linking it. It
might be surprised that we moved it.

I also improved the error message if we try to `loadWebAssemblyModule`
something that is actually say a Linux .so file and updated get_dynlibs
to filter out .so files that have an incompatible abi tag.
Set PLATFORM_TRIPLET, include platform in so names, only load compatible so files. For reasons that are a bit beyond me, `--host` and `PLATFORM_TRIPLET`
seem to be independent, in particular we've had an empty
`PLATFORM_TRIPLET`. This is unfortunate because `PLATFORM_TRIPLET`
is used to generate the SOABI config variable which in turn is used
to decide whether a .so file is a good match for loading. We'd like
for linux Pythons not to try to import emscripten .so files (it
raises `ImportError: some_file.so: invalid ELF header`). Similarly,
we'd like to avoid attempting to load linux .so files in wasm. These
platform tags are our friends.

Anyways, this PR sets `PLATFORM_TRIPLET` and ensures that .so files
built by pywasmcross are tagged with our SOABI tag.

I moved the .so file renaming from pywasmcross to buildpkg just
before running the post script. That is a better place to put it in
case the package wants to look at the .so file after linking it. It
might be surprised that we moved it.

I also improved the error message if we try to `loadWebAssemblyModule`
something that is actually say a Linux .so file and updated get_dynlibs
to filter out .so files that have an incompatible abi tag.
package:
  name: colorspacious
  version: 1.1.2
source:
  url: https://files.pythonhosted.org/packages/ab/a1/318b9aeca7b9856410ededa4f52d6f82174d1a41e64bdd70d951e532675a/colorspacious-1.1.2-py2.py3-none-any.whl
  sha256: c78befa603cea5dccb332464e7dd29e96469eebf6cd5133029153d1e69e3fd6f
requirements:
  run:
    - numpy
test:
  imports:
    - colorspacious
about:
  home: https://github.com/njsmith/colorspacious
  PyPI: https://pypi.org/project/colorspacious
  summary:
    A powerful, accurate, and easy-to-use Python library for doing colorspace
    conversions
  license: MIT

package:
  name: colorspacious
  version: 1.1.2
source:
  url: https://files.pythonhosted.org/packages/ab/a1/318b9aeca7b9856410ededa4f52d6f82174d1a41e64bdd70d951e532675a/colorspacious-1.1.2-py2.py3-none-any.whl
  sha256: c78befa603cea5dccb332464e7dd29e96469eebf6cd5133029153d1e69e3fd6f
requirements:
  run:
    - numpy
test:
  imports:
    - colorspacious
about:
  home: https://github.com/njsmith/colorspacious
  PyPI: https://pypi.org/project/colorspacious
  summary:
    A powerful, accurate, and easy-to-use Python library for doing colorspace
    conversions
  license: MIT
