[PATCH 4/5] qemu: enable parallel builds when using the jobserver class

["Martin Hundebøll" <martin@geanix.com>]

If the jobserver class is enabled, the PARALLEL_MAKE variable is unset in
favor of configuring a shared jobserver in the MAKEFLAGS variable. However,
the qemu makefile translates the missing `-j<N>` argument to `-j1` when
calling into meson / ninja. Add a patch to make the qemu makefile
consider the --jobserver-auth option too.

Signed-off-by: Martin Hundebøll <martin@geanix.com>
---
 meta/recipes-devtools/qemu/qemu.inc           |  1 +
 ...e-jobserver-auth-argument-when-calli.patch | 37 +++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 meta/recipes-devtools/qemu/qemu/0013-Makefile-preserve-jobserver-auth-argument-when-calli.patch

diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index 4501f84c2b..1f86bf5a44 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -39,6 +39,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
            file://0003-linux-user-Add-strace-for-shmat.patch \
            file://0004-linux-user-Rewrite-target_shmat.patch \
            file://0005-tests-tcg-Check-that-shmat-does-not-break-proc-self-.patch \
+           file://0013-Makefile-preserve-jobserver-auth-argument-when-calli.patch \
            file://CVE-2023-6683.patch \
            file://qemu-guest-agent.init \
            file://qemu-guest-agent.udev \
diff --git a/meta/recipes-devtools/qemu/qemu/0013-Makefile-preserve-jobserver-auth-argument-when-calli.patch b/meta/recipes-devtools/qemu/qemu/0013-Makefile-preserve-jobserver-auth-argument-when-calli.patch
new file mode 100644
index 0000000000..33db8b7ddc
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0013-Makefile-preserve-jobserver-auth-argument-when-calli.patch
@@ -0,0 +1,37 @@
+From 730530c5f01e00cdc3754ebb8f3d7ff995f3376e Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Martin=20Hundeb=C3=B8ll?= <martin@geanix.com>
+Date: Thu, 21 Sep 2023 10:57:45 +0200
+Subject: [PATCH] Makefile: preserve --jobserver-auth argument when calling
+ ninja
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Qemu wraps its call to ninja in a Makefile. Since ninja, as opposed to
+make, utilizes all CPU cores by default, the qemu Makefile translates
+the absense of a `-jN` argument into `-j1`. This breaks jobserver
+functionality, so update the -jN mangling to take the --jobserver-auth
+argument into considerationa too.
+
+Signed-off-by: Martin Hundebøll <martin@geanix.com>
+Upstream-Status: Submitted [https://gitlab.com/qemu-project/qemu/-/issues/1898]
+---
+ Makefile | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/Makefile b/Makefile
+index 8f36990335..183756018f 100644
+--- a/Makefile
++++ b/Makefile
+@@ -142,7 +142,7 @@ MAKE.k = $(findstring k,$(firstword $(filter-out --%,$(MAKEFLAGS))))
+ MAKE.q = $(findstring q,$(firstword $(filter-out --%,$(MAKEFLAGS))))
+ MAKE.nq = $(if $(word 2, $(MAKE.n) $(MAKE.q)),nq)
+ NINJAFLAGS = $(if $V,-v) $(if $(MAKE.n), -n) $(if $(MAKE.k), -k0) \
+-        $(filter-out -j, $(lastword -j1 $(filter -l% -j%, $(MAKEFLAGS)))) \
++        $(or $(filter -l% -j%, $(MAKEFLAGS)), $(if $(filter --jobserver-auth=%, $(MAKEFLAGS)),, -j1)) \
+         -d keepdepfile
+ ninja-cmd-goals = $(or $(MAKECMDGOALS), all)
+ ninja-cmd-goals += $(foreach g, $(MAKECMDGOALS), $(.ninja-goals.$g))
+-- 
+2.44.0
+
-- 
2.44.0