Not sure why I'm running into an error trying to install:

> require(devtools)
> devtools::install_github('hms-dbmi/scde', build_vignettes = FALSE)
Downloading GitHub repo hms-dbmi/scde@master
Installing scde
'/Library/Frameworks/R.framework/Resources/bin/R' --no-site-file --no-environ --no-save --no-restore CMD INSTALL  \
  '/private/var/folders/5m/jlrrrsfd719d0ks0qg48_pg80000gn/T/RtmpySfvZs/devtools457677f6f48/hms-dbmi-scde-3b04472' --library='/Library/Frameworks/R.framework/Versions/3.2/Resources/library' --install-tests 

* installing *source* package ‘scde’ ...
** libs
clang++ -I/Library/Frameworks/R.framework/Resources/include -DNDEBUG  -I/usr/local/include -I/usr/local/include/freetype2 -I/opt/X11/include -I"/Library/Frameworks/R.framework/Versions/3.2/Resources/library/Rcpp/include" -I"/Library/Frameworks/R.framework/Versions/3.2/Resources/library/RcppArmadillo/include"   -fPIC  -Wall -mtune=core2 -g -O2  -c bwpca.cpp -o bwpca.o
clang++ -I/Library/Frameworks/R.framework/Resources/include -DNDEBUG  -I/usr/local/include -I/usr/local/include/freetype2 -I/opt/X11/include -I"/Library/Frameworks/R.framework/Versions/3.2/Resources/library/Rcpp/include" -I"/Library/Frameworks/R.framework/Versions/3.2/Resources/library/RcppArmadillo/include"   -fPIC  -Wall -mtune=core2 -g -O2  -c jpmatLogBoot.cpp -o jpmatLogBoot.o
jpmatLogBoot.cpp:200:24: warning: unused variable 'maxv' [-Wunused-variable]
                double maxv=nbp.max(maxij);
                       ^
jpmatLogBoot.cpp:443:10: warning: unused variable 'maxv' [-Wunused-variable]
                double maxv=nbp.max(maxij);
                       ^
2 warnings generated.
clang++ -I/Library/Frameworks/R.framework/Resources/include -DNDEBUG  -I/usr/local/include -I/usr/local/include/freetype2 -I/opt/X11/include -I"/Library/Frameworks/R.framework/Versions/3.2/Resources/library/Rcpp/include" -I"/Library/Frameworks/R.framework/Versions/3.2/Resources/library/RcppArmadillo/include"   -fPIC  -Wall -mtune=core2 -g -O2  -c matSlideMult.cpp -o matSlideMult.o
clang++ -I/Library/Frameworks/R.framework/Resources/include -DNDEBUG  -I/usr/local/include -I/usr/local/include/freetype2 -I/opt/X11/include -I"/Library/Frameworks/R.framework/Versions/3.2/Resources/library/Rcpp/include" -I"/Library/Frameworks/R.framework/Versions/3.2/Resources/library/RcppArmadillo/include"   -fPIC  -Wall -mtune=core2 -g -O2  -c pagoda.cpp -o pagoda.o
clang++ -dynamiclib -Wl,-headerpad_max_install_names -undefined dynamic_lookup -single_module -multiply_defined suppress -L/Library/Frameworks/R.framework/Resources/lib -L/usr/local/lib -o scde.so bwpca.o jpmatLogBoot.o matSlideMult.o pagoda.o -L/Library/Frameworks/R.framework/Resources/lib -lRlapack -L/Library/Frameworks/R.framework/Resources/lib -lRblas -L/usr/local/lib/gcc/x86_64-apple-darwin13.0.0/4.8.2 -lgfortran -lquadmath -lm -F/Library/Frameworks/R.framework/.. -framework R -Wl,-framework -Wl,CoreFoundation
ld: warning: directory not found for option '-L/usr/local/lib/gcc/x86_64-apple-darwin13.0.0/4.8.2'
ld: library not found for -lgfortran
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [scde.so] Error 1
ERROR: compilation failed for package ‘scde’
* removing ‘/Library/Frameworks/R.framework/Versions/3.2/Resources/library/scde’
Error: Command failed (1)