Use environment variables if set (#288)

And trim newlines before splitting compilers

Closes #287

R/compilation-db.R

@@ -58,7 +58,7 @@ has_compilation_db <- function(desc) {
 
   out <- as.logical(field)
   check_bool(out, arg = "Config/build/compilation-database")
-  
+
   out
 }
 
@@ -193,15 +193,15 @@ compilers <- function() {
   # These variables are normally set by frontends but just in case
   env <- c(
     "current",
-    R_INCLUDE_DIR = fs::path(R.home(), "include"),
-    R_SHARE_DIR = fs::path(R.home(), "share")
+    R_INCLUDE_DIR = Sys.getenv("R_INCLUDE_DIR", unset = fs::path(R.home(), "include")),
+    R_SHARE_DIR = Sys.getenv("R_SHARE_DIR", unset = fs::path(R.home(), "share"))
   )
 
   pkgbuild::with_build_tools(
     out <- processx::run("make", c(makevars, "print-compilers"), env = env)
   )
 
-  compilers <- strsplit(out$stdout, "\n")[[1]]
+  compilers <- strsplit(trimws(out$stdout), "\n")[[1]]
 
   # Remove arguments
   compilers <- strsplit(compilers, " ")