From e05a62a968e688533f014ac556a8b32662b32ed3 Mon Sep 17 00:00:00 2001
From: Andrea Corallo <akrl@sdf.org>
Date: Sat, 21 Mar 2020 14:11:41 +0000
Subject: [PATCH] Have a fast build option triggered by env var
 NATIVE_FAST_BOOT

---
 lisp/Makefile.in        |  8 +++++---
 lisp/emacs-lisp/comp.el | 22 ++++++++++++----------
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/lisp/Makefile.in b/lisp/Makefile.in
index 8ba619656d8..035720b49b7 100644
--- a/lisp/Makefile.in
+++ b/lisp/Makefile.in
@@ -351,9 +351,11 @@ compile-main: gen-lisp compile-clean
 	      GREP_OPTIONS= grep '^;.*[^a-zA-Z]no-byte-compile: *t' $$el > /dev/null && \
 	      continue; 			     \
 	  echo "$${el}c";                            \
-	done | xargs $(XARGS_LIMIT) echo) | 	     \
-	while read chunk; do 			     \
-	  $(MAKE) compile-targets TARGETS="$$chunk"; \
+	done | xargs $(XARGS_LIMIT) echo) |	     \
+	while read chunk; do			     \
+	  $(MAKE) compile-targets		     \
+		  NATIVE_DISABLE=$(NATIVE_FAST_BOOT) \
+		  TARGETS="$$chunk";		     \
 	done
 
 .PHONY: native-compile-clean
diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index 1e348c065b5..a316d741a26 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -2234,16 +2234,18 @@ Ultra cheap impersonation of `batch-byte-compile'."
 (defun batch-byte-native-compile-for-bootstrap ()
   "As `batch-byte-compile' but used for booststrap.
 Always generate elc files too and handle native compiler expected errors."
-  (let ((byte-native-for-bootstrap t)
-        (byte-to-native-output-file nil))
-    (unwind-protect
-        (condition-case _
-            (batch-native-compile)
-          (native-compiler-error-dyn-func)
-          (native-compiler-error-empty-byte))
-      (pcase byte-to-native-output-file
-        (`(,tempfile . ,target-file)
-         (rename-file tempfile target-file t))))))
+  (if (equal (getenv "NATIVE_DISABLE") "1")
+      (batch-byte-compile)
+    (let ((byte-native-for-bootstrap t)
+          (byte-to-native-output-file nil))
+      (unwind-protect
+          (condition-case _
+              (batch-native-compile)
+            (native-compiler-error-dyn-func)
+            (native-compiler-error-empty-byte))
+        (pcase byte-to-native-output-file
+          (`(,tempfile . ,target-file)
+           (rename-file tempfile target-file t)))))))
 
 ;;;###autoload
 (defun native-compile-async (paths &optional recursively load)
-- 
2.39.5