尝试安装pcalg软件包时，出现以下错误：
ld: warning: directory not found for option '-L/usr/local/gfortran/lib'
ld: library not found for -lgfortran
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [pcalg.so] Error 1
ERROR: compilation failed for package ‘pcalg’
* removing ‘/Library/Frameworks/R.framework/Versions/3.4/Resources/library/pcalg’
The downloaded source packages are in
‘/private/var/folders/54/nwpr9hkn49b1m4h3hjmwph6r0000gn/T/RtmpREqD5T/downloaded_packages’
Warning message:
In install.packages("pcalg") :
installation of package ‘pcalg’ had non-zero exit status
我假设这是因为gfortan包现在gcc，但我不知道如何将其指向正确的位置。有人知道如何解决这个问题吗？