Installation error

[Jiayi-Wang-Joey]

Hi

Thanks for your work of FACETS.
I am a MacOS user. And I have the following error when installation.

─  installing *source* package ‘facets’ ...
   ** using staged installation
   ** libs
   clang -mmacosx-version-min=10.13 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG   -I/usr/local/include   -fPIC  -Wall -g -O2  -Wall -pedantic -fdiagnostics-color=always -c 000.init.c -o 000.init.o
   gfortran -mmacosx-version-min=10.13 -fno-optimize-sibling-calls  -fPIC  -Wall -g -O2  -c cbs2rank.f -o cbs2rank.o
   make: gfortran: No such file or directory
   make: *** [cbs2rank.o] Error 1
   ERROR: compilation failed for package ‘facets’
─  removing ‘/private/var/folders/jp/zptlfyzn5z3dz53d2c0hcft40000gn/T/Rtmp1ciZQq/Rinst68d32ead3659/facets’
         -----------------------------------
   ERROR: package installation failed
Error: Failed to install 'facets' from GitHub:
  System command 'R' failed, exit status: 1, stdout & stderr were printed

Can you help me with this?
Thanks in advance!

Kind regards,
Jiayi