[R-pkg-devel] clang: error: unsupported option '-fopenmp'

Hello, All:


 ????? I'm getting "clang: error: unsupported option '-fopenmp'" when 
trying to build "https://github.com/helske/bssm" under macOS 10.14.14 
with R 3.6.0;? see below.


 ????? What do you suggest?


 ????? Thanks,
 ????? Spencer Graves


p.s.? I assume I have to install compiler(s).? However, I've so far been 
unable to find instructions that are sufficiently current to convince me 
I might not do more harm than good following them.


 > R CMD build bssm
* checking for file ?bssm/DESCRIPTION? ... OK
* preparing ?bssm?:
* checking DESCRIPTION meta-information ... OK
* cleaning src
* installing the package to build vignettes
 ????? -----------------------------------
* installing *source* package ?bssm? ...
** using staged installation
** libs
clang++ -std=gnu++11 
-I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/BH/include" 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/Rcpp/include" 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/RcppArmadillo/include" 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/ramcmc/include" 
-I"/Library/Frameworks/R.framework/Versions/3.6/Resources/library/sitmo/include" 
-isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk 
-I/usr/local/include -fopenmp -fPIC? -Wall -g -O2? -c R_approx.cpp -o 
R_approx.o
clang: error: unsupported option '-fopenmp'
make: *** [R_approx.o] Error 1
ERROR: compilation failed for package ?bssm?
* removing 
?/private/var/folders/mh/mrm_14nx19g13lsnj9zmvwjr0000gn/T/RtmppA2gBg/Rinst24427c5cbfeb/bssm?
 ????? -----------------------------------
ERROR: package installation failed