Unable to install sass (R 3.6.3, Ubuntu 20.04 LTS)

I am trying to install sass in R 3.6.3 in order to install the gt package, but to no avail. I have checked a previous post with a similar problem but it has not solved my issue, so I would appreciate any help.

I have tried installing from CRAN:

install.packages("sass")

but I keep getting this error message:

Installing package into '/home/christabucao/R/x86_64-pc-linux-gnu-library/3.6'
(as 'lib' is unspecified)
trying URL 'https://cloud.r-project.org/src/contrib/sass_0.2.0.tar.gz'
Content type 'application/x-gzip' length 2960582 bytes (2.8 MB)
==================================================
downloaded 2.8 MB

* installing *source* package ‘sass’ ...
** package ‘sass’ successfully unpacked and MD5 sums checked
** using staged installation
** libs
/usr/share/R/share/make/shlib.mk:14: warning: overriding recipe for target 'shlib-clean'
Makevars:12: warning: ignoring old recipe for target 'shlib-clean'
gcc -std=gnu99 -I"/usr/share/R/include" -DNDEBUG -I./libsass/include    -fpic  -g -O2 -fdebug-prefix-map=/build/r-base-jbaK_j/r-base-3.6.3=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -g  -c compile.c -o compile.o
gcc -std=gnu99 -I"/usr/share/R/include" -DNDEBUG -I./libsass/include    -fpic  -g -O2 -fdebug-prefix-map=/build/r-base-jbaK_j/r-base-3.6.3=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -g  -c init.c -o init.o
MAKEFLAGS= CC="gcc -std=gnu99" CFLAGS="-g -O2 -fdebug-prefix-map=/build/r-base-jbaK_j/r-base-3.6.3=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -g " CXX="g++ -std=gnu++11" AR="ar" LDFLAGS="-Wl,-Bsymbolic-functions -Wl,-z,relro" make -C libsass
make[1]: Entering directory '/tmp/RtmpkWUbMj/R.INSTALL84692da9e653/sass/src/libsass'
gcc -std=gnu99 -g -O2 -fdebug-prefix-map=/build/r-base-jbaK_j/r-base-3.6.3=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -g  -O2 -I ./include  -fPIC -c -o src/cencode.o src/cencode.c
g++ -std=gnu++11 -Wall -O2 -std=c++11 -I ./include  -fPIC -c -o src/ast.o src/ast.cpp
In file included from src/ast.hpp:19:0,
                 from src/ast.cpp:2:
src/util.hpp: In function 'T Sass::absmod(const T&, const T&)':
src/util.hpp:28:11: error: 'fmod' is not a member of 'std'
     T m = std::fmod(n, r);
           ^
src/util.hpp:28:11: note: suggested alternative:
In file included from /usr/include/features.h:461:0,
                 from /home/linuxbrew/.linuxbrew/Cellar/gcc/5.5.0_7/include/c++/5.5.0/x86_64-unknown-linux-gnu/bits/os_defines.h:39,
                 from /home/linuxbrew/.linuxbrew/Cellar/gcc/5.5.0_7/include/c++/5.5.0/x86_64-unknown-linux-gnu/bits/c++config.h:489,
                 from /home/linuxbrew/.linuxbrew/Cellar/gcc/5.5.0_7/include/c++/5.5.0/string:38,
                 from src/sass.hpp:55,
                 from src/ast.cpp:1:
/usr/include/x86_64-linux-gnu/bits/mathcalls.h:168:1: note:   'fmod'
 __MATHCALL (fmod,, (_Mdouble_ __x, _Mdouble_ __y));
 ^
make[1]: *** [Makefile:219: src/ast.o] Error 1
make[1]: Leaving directory '/tmp/RtmpkWUbMj/R.INSTALL84692da9e653/sass/src/libsass'
make: *** [Makevars:7: libsass/lib/libsass.a] Error 2
ERROR: compilation failed for package ‘sass’
* removing ‘/home/christabucao/R/x86_64-pc-linux-gnu-library/3.6/sass’
Warning in install.packages :
  installation of package 'sass' had non-zero exit status

The downloaded source packages are in
	'/tmp/RtmpaNzJsA/downloaded_packages'

I have also tried installing from Github:

>     devtools::install_github("rstudio/sass")
Downloading GitHub repo rstudio/sass@master
✓  checking for file ‘/tmp/RtmpaNzJsA/remotesd9b4ef6417a/rstudio-sass-0aa3469/DESCRIPTION’ ...
─  preparing ‘sass’:
✓  checking DESCRIPTION meta-information ...
─  cleaning src
─  checking for LF line-endings in source and make files and shell scripts
─  checking for empty or unneeded directories
   Removed empty directory ‘sass/scripts’
─  building ‘sass_0.2.0.tar.gz’

but I also get a similar error message:

make[1]: *** [Makefile:219: src/ast.o] Error 1
make[1]: Leaving directory '/tmp/Rtmp0wv1q2/R.INSTALL856e44869893/sass/src/libsass'
make: *** [Makevars:7: libsass/lib/libsass.a] Error 2
ERROR: compilation failed for package ‘sass’
* removing ‘/home/christabucao/R/x86_64-pc-linux-gnu-library/3.6/sass’
Error: Failed to install 'sass' from GitHub:
  (converted from warning) installation of package '/tmp/RtmpaNzJsA/filed9b20748aa4/sass_0.2.0.tar.gz' had non-zero exit status

I would appreciate any advice. Thanks!

Session Info:

> sessionInfo()
R version 3.6.3 (2020-02-29)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 20.04 LTS

Referred here by sass's README