@msz59 Re: (1), thanks for the tip! That solves the issue.
Re: (2), I just corrected my previous message. I meant to write that I have requested that the flang formula be merged into the llvm formula but have received no response. The issue I’m encountering is that clang can’t find ISO_Fortran_binding.h because the flang formula installs in a separate location from the llvm formula, which is understandable for two different formulas. To wit,
git clone git@github.com:berkeleylab/iso_fortran_binding_m.git
cd iso_fortran_binding_m
FPM_CC=clang FPM_FC=flang-new fpm test
yields
In file included from ././src/cfi_function_wrappers.c:3:
././src/cfi_function_wrappers.h:7:10: fatal error: 'ISO_Fortran_binding.h' file not found
7 | #include <ISO_Fortran_binding.h>
| ^~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
By contrast, FPM_CC=gcc-13 FPM_FC=gfortran-13 fpm test builds without error and reports passing tests (caveat: replacing 13 with 14 or 15 fails to build for reasons that I haven’t diagnosed). I suspect the difference between LLVM and GCC is that gcc-13 and gfortran-13 are installed by one gcc@13 formula and they therefore install to a common path or at least each language front end knows where to find the other’s files.