Installing a new version and loading an old version failed because it can't find spam.so

[GeraldCNelson]

I'm on a mac. I have copied the complete set of error messages below. It may have something to do with my gfortran installation though. The error message mentions gfortran5 (/usr/local/gfortran/lib/libgfortran.5.dylib). When I attempt to use home-brew to install gfortran, I'm told that 'gcc 10.2.0_2 is already installed and up-to-date'

> install_github('AndySouth/rworldmap', build_vignettes=TRUE) 
Downloading GitHub repo AndySouth/rworldmap@HEAD
✓  checking for file ‘/private/var/folders/bv/881_rsvd2kv83c13yywwc_xh0000gp/T/RtmpDM0dPE/remotes9571339294c0/andysouth-rworldmap-22e1db5/DESCRIPTION’ ...
─  preparing ‘rworldmap’:
✓  checking DESCRIPTION meta-information ...
   Warning: /private/var/folders/bv/881_rsvd2kv83c13yywwc_xh0000gp/T/RtmprQ6So0/Rbuildc73847e4460a/rworldmap/man/countriesCoarse.Rd:10: unexpected TEXT '"sp"', expecting ']'
   Warning: /private/var/folders/bv/881_rsvd2kv83c13yywwc_xh0000gp/T/RtmprQ6So0/Rbuildc73847e4460a/rworldmap/man/countriesCoarseLessIslands.Rd:10: unexpected TEXT '"sp"', expecting ']'
   Warning: /private/var/folders/bv/881_rsvd2kv83c13yywwc_xh0000gp/T/RtmprQ6So0/Rbuildc73847e4460a/rworldmap/man/countriesLow.Rd:10: unexpected TEXT '"sp"', expecting ']'
─  installing the package to build vignettes
         -----------------------------------
─  installing *source* package ‘rworldmap’ ...
   ** using staged installation
   ** R
   ** data
   *** moving datasets to lazyload DB
   ** inst
   ** byte-compile and prepare package for lazy loading
   Error in dyn.load(file, DLLpath = DLLpath, ...) : 
     unable to load shared object '/Library/Frameworks/R.framework/Versions/4.0/Resources/library/spam/libs/spam.so':
     dlopen(/Library/Frameworks/R.framework/Versions/4.0/Resources/library/spam/libs/spam.so, 6): Library not loaded: /usr/local/gfortran/lib/libgfortran.5.dylib
     Referenced from: /Library/Frameworks/R.framework/Versions/4.0/Resources/library/spam/libs/spam.so
     Reason: image not found
   Calls: <Anonymous> ... namespaceImport -> loadNamespace -> library.dynam -> dyn.load
   Execution halted
   ERROR: lazy loading failed for package ‘rworldmap’
─  removing ‘/private/var/folders/bv/881_rsvd2kv83c13yywwc_xh0000gp/T/RtmprQ6So0/Rinstc7385bb25f65/rworldmap’
         -----------------------------------
   ERROR: package installation failed
 Error: Failed to install 'rworldmap' from GitHub:
  System command 'R' failed, exit status: 1, stdout + stderr (last 10 lines):
E>   unable to load shared object '/Library/Frameworks/R.framework/Versions/4.0/Resources/library/spam/libs/spam.so':
E>   dlopen(/Library/Frameworks/R.framework/Versions/4.0/Resources/library/spam/libs/spam.so, 6): Library not loaded: /usr/local/gfortran/lib/libgfortran.5.dylib
E>   Referenced from: /Library/Frameworks/R.framework/Versions/4.0/Resources/library/spam/libs/spam.so
E>   Reason: image not found
E> Calls: <Anonymous> ... namespaceImport -> loadNamespace -> library.dynam -> dyn.load
E> Execution halted
E> ERROR: lazy loading failed for package ‘rworldmap’
E> * removing ‘/private/var/folders/bv/881_rsvd2kv83c13yywwc_xh0000gp/T/RtmprQ6So0/Rinstc7385bb25f65/rworldmap’
E>       -----------------------------------
E> ERROR: package installation failed 
8.
stop(remote_install_error(remotes[[i]], e)) 
7.
value[[3L]](cond) 
6.
tryCatchOne(expr, names, parentenv, handlers[[1L]]) 
5.
tryCatchList(expr, classes, parentenv, handlers) 
4.
tryCatch(res[[i]] <- install_remote(remotes[[i]], ...), error = function(e) {
    stop(remote_install_error(remotes[[i]], e))
}) 
3.
install_remotes(remotes, auth_token = auth_token, host = host, 
    dependencies = dependencies, upgrade = upgrade, force = force, 
    quiet = quiet, build = build, build_opts = build_opts, build_manual = build_manual, 
    build_vignettes = build_vignettes, repos = repos, type = type,  ... 
2.
pkgbuild::with_build_tools({
    ellipsis::check_dots_used(action = getOption("devtools.ellipsis_action", 
        rlang::warn))
    { ... 
1.
install_github("AndySouth/rworldmap", build_vignettes = TRUE)