callr error on install

[jzadra]

Downloading GitHub repo hrbrmstr/albersusa@master
from URL https://api.github.com/repos/hrbrmstr/albersusa/zipball/master
Installing albersusa
trying URL 'https://cran.rstudio.com/src/contrib/classInt_0.1-24.tar.gz'
Content type 'application/x-gzip' length 19194 bytes (18 KB)
==================================================
downloaded 18 KB

Installing classInt
trying URL 'https://cran.rstudio.com/src/contrib/e1071_1.6-8.tar.gz'
Content type 'application/x-gzip' length 581513 bytes (567 KB)
==================================================
downloaded 567 KB

Installing e1071
Installation failed: NULL : 'rcmd_safe_env' is not an exported object from 'namespace:callr'
Installation failed: NULL : 'rcmd_safe_env' is not an exported object from 'namespace:callr'
trying URL 'https://cran.rstudio.com/src/contrib/e1071_1.6-8.tar.gz'
Content type 'application/x-gzip' length 581513 bytes (567 KB)
==================================================
downloaded 567 KB

Skipping e1071, it is already being installed.
trying URL 'https://cran.rstudio.com/src/contrib/rgdal_1.2-15.tar.gz'
Content type 'application/x-gzip' length 1648779 bytes (1.6 MB)
==================================================
downloaded 1.6 MB

Installing rgdal
Installation failed: NULL : 'rcmd_safe_env' is not an exported object from 'namespace:callr'
trying URL 'https://cran.rstudio.com/src/contrib/rgeos_0.3-26.tar.gz'
Content type 'application/x-gzip' length 250574 bytes (244 KB)
==================================================
downloaded 244 KB

Installing rgeos
Installation failed: NULL : 'rcmd_safe_env' is not an exported object from 'namespace:callr'
trying URL 'https://cran.rstudio.com/src/contrib/sf_0.5-5.tar.gz'
Content type 'application/x-gzip' length 7734623 bytes (7.4 MB)
==================================================
downloaded 7.4 MB

Installing sf
trying URL 'https://cran.rstudio.com/src/contrib/classInt_0.1-24.tar.gz'
Content type 'application/x-gzip' length 19194 bytes (18 KB)
==================================================
downloaded 18 KB

Skipping classInt, it is already being installed.
trying URL 'https://cran.rstudio.com/src/contrib/e1071_1.6-8.tar.gz'
Content type 'application/x-gzip' length 581513 bytes (567 KB)
==================================================
downloaded 567 KB

Skipping e1071, it is already being installed.
Installation failed: NULL : 'rcmd_safe_env' is not an exported object from 'namespace:callr'
Installation failed: NULL : 'rcmd_safe_env' is not an exported object from 'namespace:callr'