NaMaster installation CFITSIO issue

[JamesAmato]

I'm trying to set up NaMaster to be installed as part of a pyproject.toml. It's unable to find CFITSIO. I'm trying to get this set up as a dependency for another library, so I'd like to get the installation simplified.

I am able to install it using conda in a fresh environment (note that it reports being version 2.2.1).

I use:

`[tool.poetry]
name = "test_install_namaster"
version = "0.0.0"
description = ""
authors = ["JamesAmato [email protected]"]
readme = "README.md"

[tool.poetry.dependencies]
python = "^3.9"
healpy = "^1.17.1"

[tool.poetry.group.dev.dependencies]
pytest = "^8.0.1"
pylint = "^3.0.3"

[build-system]
requires = ["poetry-core>=1.0.0"]
build-backend = "poetry.core.masonry.api"`

This works just fine. Note that healpy is in there, so CFITSIO should be installed.

When I try to poetry add pymaster or poetry add pymaster=2.2.1, both fail, with:
" checking for CFITSIO... no
checking for ffgnrwll in -lcfitsio... no
configure: error: could not find the cfitsio library
ERROR: failed to configure HEALPix. Check CFITSIO is installed and reachable.
error: Failed to install libchealpix."

At the end is the message: "Note: This error originates from the build backend, and is likely not a problem with poetry but with pymaster (2.2.1) not supporting PEP 517 builds. You can verify this by running 'pip wheel --no-cache-dir --use-pep517 "pymaster (==2.2.1)"'."

Running that command also fails, with similar results.