Remove threads arg of install_deps()

If `Ncpus` was also specified, that led to an error.
Closes #153.

NEWS.md

@@ -3,6 +3,9 @@
 * `install_github()`'s previously deprecated `username` argument has been
   removed. (#142)
 
+* `install_deps()`'s `threads` argument has been removed, use the `Ncpus`
+  argument instead (#153, #154)
+
 # Development
 
 * Remotes can be forced to use only its internal code by setting the

R/install.R

@@ -102,8 +102,6 @@ safe_build_package <- function(pkgdir, build_opts, dest_path, quiet, use_pkgbuil
 #' Install package dependencies if needed.
 #'
 #' @inheritParams package_deps
-#' @param threads Number of threads to start, passed to
-#'   \code{\link[utils]{install.packages}} as \code{Ncpus}.
 #' @param ... additional arguments passed to \code{\link[utils]{install.packages}}.
 #' @param build If \code{TRUE} build the pacakge before installing.
 #' @param build_opts Options to pass to `R CMD build`.
@@ -112,7 +110,6 @@ safe_build_package <- function(pkgdir, build_opts, dest_path, quiet, use_pkgbuil
 #' \dontrun{install_deps(".")}
 
 install_deps <- function(pkgdir = ".", dependencies = NA,
-                         threads = getOption("Ncpus", 1),
                          repos = getOption("repos"),
                          type = getOption("pkgType"),
                          ...,
@@ -135,7 +132,6 @@ install_deps <- function(pkgdir = ".", dependencies = NA,
     packages,
     dependencies = dep_deps,
     ...,
-    Ncpus = threads,
     quiet = quiet,
     upgrade = upgrade,
     build = build,