From c8a32f62c78fdb6cccb04ccfa321c239bde006e3 Mon Sep 17 00:00:00 2001
From: Alexandre Duret-Lutz <adl@lrde.epita.fr>
Date: Thu, 26 Nov 2020 09:58:51 +0100
Subject: [PATCH] debian: use -flto=jobserver.

* debian/rules: Adjust to use the jobserver, don't pass 'u' to ar,
and fix typo introduced by fe694e2ba.
---
 debian/rules | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/debian/rules b/debian/rules
index 4a522c0d9..0193e9a62 100755
--- a/debian/rules
+++ b/debian/rules
@@ -26,23 +26,29 @@ LTOPLUG := $(shell gcc -v 2>&1 | \
 
 # ARFLAGS is for Automake
 # AR_FLAGS is for Libtool
+# These activate the LTO pluggin, but also remove the 'u' option
+# from ar, since its now ignored with Debian's default to 'D'.
 LTOSETUP =					    \
   LDFLAGS='-fuse-linker-plugin'			    \
   NM='nm --plugin $(LTOPLUG)'			    \
-  ARFLAGS='cru --plugin $(LTOPLUG)'		    \
-  AR_FLAGS='cru --plugin $(LTOPLUG)'		    \
-  RANLIB='ranlib --plugin $(LTOPLUG)'
+  ARFLAGS='cr --plugin $(LTOPLUG)'		    \
+  AR_FLAGS='cr --plugin $(LTOPLUG)'		    \
+  RANLIB='ranlib --plugin $(LTOPLUG)'		    \
   VALGRIND=false
 GCDADIR := $(shell pwd)/gcda
-PROFW = -Wno-error=coverage-mismatch
-PRO1SETUP =							\
-  CFLAGS='-flto -fprofile-generate=$(GCDADIR) $(PROFW)'		\
-  CXXFLAGS='-flto -fprofile-generate=$(GCDADIR) $(PROFW)'
-PRO2SETUP =						\
-  CFLAGS='-flto -fprofile-use=$(GCDADIR) $(PROFW) -fprofile-correction'	\
-  CXXFLAGS='-flto -fprofile-use=$(GCDADIR) $(PROFW) -fprofile-correction'
+
+FLTO = -flto=jobserver -Wno-error=coverage-mismatch
+PRO1SETUP = \
+  CFLAGS="$(FLTO) -fprofile-generate=$(GCDADIR)" \
+  CXXFLAGS="$(FLTO) -fprofile-generate=$(GCDADIR)"
+PRO2SETUP = \
+  CFLAGS="$(FLTO) -fprofile-use=$(GCDADIR) -fprofile-correction" \
+  CXXFLAGS="$(FLTO) -fprofile-use=$(GCDADIR) -fprofile-correction"
 PYDEFAULT=$(shell py3versions --default)
 PYOTHERS=$(filter-out $(PYDEFAULT), $(shell py3versions --supported))
+# This hack causes + to appear in front of the link step, so that
+# LTO can be done using GNU Make's job server.
+MAKEOVERRIDES += AM_V_CXXLD=+ AM_V_CCLD=+
 
 # We want to build Spot twice: once to get profile data, and a second
 # time to use it.
@@ -53,7 +59,7 @@ override_dh_auto_configure:
 	  --disable-static PYTHON=/usr/bin/$(PYDEFAULT)
 	dh_auto_build
 	dh_auto_test
-	make clean
+	$(MAKE) clean
 	dh_auto_configure -- $(PRO2SETUP) $(LTOSETUP)	\
 	  --disable-devel --enable-optimizations	\
 	  --disable-static PYTHON=/usr/bin/$(PYDEFAULT)