Accept -jN arg to build-all-cores

and don't redirect *stdout* and *stderr* if -j1.

You can specify more than one target, and they will follow one another
with no chance of overlap since it's sequential. This should give more-or-less
the same behavior as the deleted crossbuild-runner/build-all.sh script.

We can add a few more indicators of where each build starts,
but this is probably adequate for now.

build-all-cores.sh

@@ -2,7 +2,6 @@
 ./run-sbcl.sh --noprint --disable-debugger $* <<\EOF
 (defvar *configs-to-build* (cdr *posix-argv*))
 
-;;; TODO: allow this to be specified on the command line
 (defparameter *jobs*
   (max 1
        #+unix
@@ -11,7 +10,22 @@
                                       (function sb-alien:long sb-alien:int))
                sb-unix::sc-nprocessors-onln)
               2)))
-(format t "~&Using up to ~D job~:P~%" *jobs*)
+
+(let ((first (car *configs-to-build*)))
+  (if (and (stringp first)
+           (>= (length first) 2)
+           (string= first "-j" :end1 2))
+      ;; allow "-jN" as two args
+      (cond ((= (length first) 2)
+             (pop *configs-to-build*)
+             (setq *jobs* (parse-integer (pop *configs-to-build*))))
+            ((digit-char-p (char first 2)) ; or "-jN" as one arg
+             (setq *jobs* (parse-integer first :start 2))
+             (pop *configs-to-build*))
+            (t
+             (error "-j requires a number")))))
+
+(when (> *jobs* 1) (format t "~&Using up to ~D job~:P~%" *jobs*))
 
 ;;; I should probably have a way to add a fixed set of features in
 ;;; for an architecture, such as :LITTLE-ENDIAN for x86{-64}.
@@ -102,6 +116,7 @@ obj/xbuild/{cfg}.core: obj/xbuild/{cfg}/xc.core
                       *all-configurations*))))
 
 (ensure-directories-exist "obj/xbuild/")
+;; if it's just one target this could exec() instead
 (defvar *process*
   (run-program "make"
                `(,(format nil "-j~D" *jobs*)

crossbuild-runner/pass-1.lisp

@@ -12,10 +12,12 @@
   ;; (format t "~&added features: ~S~%" add-features)
   (ensure-directories-exist objroot)
   (defvar *sbcl-host-obj-prefix* objroot)
-  (setq sb-sys:*stdout* (open (format nil "~A/stdout" objroot) :direction :output
-                              :if-does-not-exist :create :if-exists :supersede)
-        sb-sys:*stderr* (open (format nil "~A/stderr" objroot) :direction :output
-                              :if-does-not-exist :create :if-exists :supersede))
+  (let ((makeflags (sb-ext:posix-getenv "MAKEFLAGS")))
+    (when (search "--jobserver-fds" makeflags)
+      (setq sb-sys:*stdout* (open (format nil "~A/stdout" objroot) :direction :output
+                                  :if-does-not-exist :create :if-exists :supersede)
+            sb-sys:*stderr* (open (format nil "~A/stderr" objroot) :direction :output
+                                  :if-does-not-exist :create :if-exists :supersede))))
   (defvar *sbcl-local-target-features-file* ltf)
   (with-open-file (*standard-output* ltf :direction :output
                                      :if-does-not-exist :create

crossbuild-runner/pass-2.lisp

@@ -9,11 +9,13 @@
   (defparameter *host-obj-prefix* (format nil "~A/from-host/" build-dir))
   (defparameter *target-obj-prefix* objroot)
   (defparameter *build-dependent-generated-sources-root* objroot)
-  (setq sb-sys:*stdout* (open (format nil "~A/stdout" objroot) :direction :output
-                              :if-does-not-exist :create :if-exists :supersede)
-        sb-sys:*stderr* (open (format nil "~A/stderr" objroot) :direction :output
-                              :if-does-not-exist :create :if-exists :supersede)))
-(setf (sb-impl::fd-stream-buffering sb-sys:*stdout*) :line)
+  (let ((makeflags (sb-ext:posix-getenv "MAKEFLAGS")))
+    (when (search "--jobserver-fds" makeflags)
+      (setq sb-sys:*stdout* (open (format nil "~A/stdout" objroot) :direction :output
+                                  :if-does-not-exist :create :if-exists :supersede)
+            sb-sys:*stderr* (open (format nil "~A/stderr" objroot) :direction :output
+                                  :if-does-not-exist :create :if-exists :supersede))
+      (setf (sb-impl::fd-stream-buffering sb-sys:*stdout*) :line))))
 (load "src/cold/set-up-cold-packages.lisp")
 (load "src/cold/defun-load-or-cload-xcompiler.lisp")
 (load-or-cload-xcompiler #'host-load-stem)