DEV: meson: add a conda environment file for Meson
DEV: meson: add a conda environment file for Meson

Note: this works on Linux and macOS, and probably on other
common Unix-like systems. But not on Windows, there's no
pkg-config there (that's the main difference; the Meson build
does work on Windows but only with a single Mingw toolchain,
the conda-forge compilers are not yet tested).

zerothi/scipy,endolith/scipy,andyfaff/scipy,andyfaff/scipy,Stefan-Endres/scipy,perimosocordiae/scipy,WarrenWeckesser/scipy,vigna/scipy,WarrenWeckesser/scipy,scipy/scipy,mdhaber/scipy,scipy/scipy,WarrenWeckesser/scipy,andyfaff/scipy,andyfaff/scipy,rgommers/scipy,zerothi/scipy,Stefan-Endres/scipy,scipy/scipy,mdhaber/scipy,endolith/scipy,anntzer/scipy,zerothi/scipy,perimosocordiae/scipy,zerothi/scipy,endolith/scipy,vigna/scipy,scipy/scipy,ilayn/scipy,rgommers/scipy,mdhaber/scipy,anntzer/scipy,andyfaff/scipy,ilayn/scipy,endolith/scipy,Stefan-Endres/scipy,scipy/scipy,zerothi/scipy,endolith/scipy,endolith/scipy,perimosocordiae/scipy,Stefan-Endres/scipy,WarrenWeckesser/scipy,scipy/scipy,mdhaber/scipy,rgommers/scipy,zerothi/scipy,vigna/scipy,perimosocordiae/scipy,Stefan-Endres/scipy,anntzer/scipy,mdhaber/scipy,perimosocordiae/scipy,vigna/scipy,anntzer/scipy,ilayn/scipy,rgommers/scipy,anntzer/scipy,mdhaber/scipy,WarrenWeckesser/scipy,Stefan-Endres/scipy,ilayn/scipy,vigna/scipy,anntzer/scipy,rgommers/scipy,ilayn/scipy,ilayn/scipy,WarrenWeckesser/scipy,andyfaff/scipy,perimosocordiae/scipy