Project using meson to build has issues detecting libraries.

[andyfaff]

First time poster. I'm trying to use cibuildwheel (in a GH build action) to make scipy wheels. Recent scipy uses meson to build the project. I'm having an issue using cibuildwheel to build on win_AMD64.

One of the dependencies for scipy is openblas. As part of CIBW_BEFORE_BUILD script I download a zipfile containing the openblas include, lib, bin directories to a known location, C:\opt. There is an openblas.pc file in C:\opt\openblas\if_32\64\lib\pkgconfig. If I use pkg-config in the CIBW_BEFORE_BUILD script the openblas library is detected.
The invocation of pkg-config in the CIBW_BEFORE_BUILD is PKG_CONFIG_PATH=/mnt/c/opt/openblas/if_32/64/lib/pkgconfig pkg-config --list-all

However, when I try to use cibuildwheel to make the wheels the meson build fails to detect the installation of openblas, even if the environment variable:
CIBW_ENVIRONMENT: PKG_CONFIG_PATH=c:\\opt\\openblas\\if_32\\64\\lib\\pkgconfig is set.

I should note that scipy already has a separate CI job building the project on GH actions using meson. So I don't think it's a meson problem per-se, but something to do with how cibuildwheel starts the build.

The github actions log, the GHactions file, the CIBW_BEFORE_BUILD script.

[andyfaff]

I managed to find out the solution to my question. In the CIBW_BEFORE_BUILD script (run as bash), I was unzipping the openBLAS library into /mnt/c/opt. It turns out this is very different to unzipping to /c/opt. When I unzip to the latter pkg-config can find the openBLAS using PKG_CONFIG_PATH=c:\\opt