clang error after upgrading to macOS Big Sur

Upgraded macOS from Catalina to Big Sur today. So far almost no trouble occured after this OS upgrade except that there is an error when I tried to compile some program with using gfortran such as,

clang: error: invalid version number in '-mmacosx-version-min=11.0'

But this was solved by updating Xcode via App Store.

I prefer the appearance of Big Sur to Catalina ;)