shtools 4.8 failed to build on apple silicon

[chenrui333]

Currently the release build 4.8 does not build successfully on Apple Silicon.

==> make fortran
mkdir -pv /private/tmp/shtools-20210126-32972-qfciqk/SHTOOLS-4.8/lib
mkdir -pv /private/tmp/shtools-20210126-32972-qfciqk/SHTOOLS-4.8/include
/Applications/Xcode.app/Contents/Developer/usr/bin/make -C src -f Makefile all F95="gfortran" F95FLAGS="-m64 -fPIC -O3 -std=gnu -ffast-math" LIBNAME="SHTOOLS" LAPACK_FLAGS="" LIBPATH="/private/tmp/shtools-20210126-32972-qfciqk/SHTOOLS-4.8/lib" MODPATH="/private/tmp/shtools-20210126-32972-qfciqk/SHTOOLS-4.8/include"
gfortran -c -m64 -fPIC -O3 -std=gnu -ffast-math ftypes.f95
gfortran: error: unrecognized command-line option '-m64'
make[1]: *** [ftypes.mod] Error 1
make: *** [fortran] Error 2
/usr/bin/curl --version
/usr/libexec/java_home --xml --failfast

relates to Homebrew/homebrew-core#69767

[MarkWieczorek]

Thanks for creating the issue: this will be fixed in the next release (ETA, a couple months). As far as I can tell, we just need to remove the -m64 flag, which is largely irrelevant today anyways....

[MarkWieczorek]

This issue was brought up in the MacPorts discussions, and it was noted that latest devel version of gcc for Apple's ARM now accepts the -m64 flag: https://trac.macports.org/ticket/62109

I will wait until the next macports gcc release and try rebuilding for ARM at that time.